Answer:
Step-by-step explanation:
To solve indices problems you need to know the laws of indices.
The laws will guide you in answering any problem related to indices, these laws are for a ≠ 0
law 1
aᵇ * aⁿ = aᵇ⁺ⁿ
example 5³ * 5⁵ = 5³⁺⁵= 5⁸
law 2
aᵇ / aⁿ = aᵇ⁻ⁿ
example 7⁵/ 7³ = 7⁵⁻³ = 7²
law 3
(aᵇ)ⁿ = aᵇⁿ
example (5³)⁴ = 5³ * 5⁴ = 5¹²
law 4
a⁰ = 1
example 8⁰ = 1
law 5
a⁻ⁿ = 1/aⁿ
example 7⁻² = 1/7² = 1/49
law 6
a^¹/ₙ = ⁿ√a
example 27^¹/₃ = ∛27 = 3
law 7
a^ᵇ/ₙ = (ⁿ√a)ᵇ = ⁿ√aᵇ
example 8^²/₃ = (∛8)² = (2)² = 4
Write down the nth term of the following sequence:
7 2 -3 -8 -13
With steps and explanation please,!!
Answer:
see explanation
Step-by-step explanation:
This is an arithmetic sequence with n th term
• [tex]a_{n}[/tex] = a + (n - 1)d
where a is the first term and d the common difference
d = 2 - 7 = - 3 - 2 = - 5 and a = 7, hence
[tex]a_{n}[/tex] = 7 - 5(n - 1) = 7 - 5n + 5 = 12 - 5n
[tex]a_{n}[/tex] = 12 - 5n ← n th term formula
~~THIS IS MULTIPLE CHOICE ~~
someone help me please I'm honestly lost
(PiCtUrE AtTaChEd)
Answer:
Derek delivers 10 magazines per hour.
Step-by-step explanation:
in the bottom of the table, M(h), the magazine number decreases by 10 every hour. So it takes him 1 hour for every 10 magazinesderek delivers ten magazines per hr
Use the figure below to find the long leg Help plzzz
Answer: The answer is 7√3
Step-by-step explanation:
Since the hypotenuse is twice as long as the shortest leg and the triangle is 30°-60°-90°, therefore the shortest leg is 7 (not the answer to your question) and the other leg is 7√3. I hope this helps :)
Answer:
D. 7√3Step-by-step explanation:
I just did this question and this was the answer that was right for me :) Hope this helps!
A right rectangular prism's edge lengths are 7 1/ 4 inches, 8 inches, and 9 inches. How many unit cubes with edge lengths of 1 2 inch can fit inside the prism? A) 224 unit cubes B) 940 unit cubes C) 1360 unit cubes D) 4176 unit cubes
Answer:
D) 4176 unit cubes
Step-by-step explanation:
Length of the right rectangular prism [tex]=7\frac{1}{4}[/tex] inches
Width of the right rectangular prism [tex]=8[/tex] inches
Height of the right rectangular prism [tex]=9[/tex] inches
Then volume of the right rectangular prism = (Length)(Width)(Height)
[tex]=\left(7\frac{1}{4}\right)\left(8\right)\left(9\right)[/tex]
[tex]=\left(7.25\right)\left(8\right)\left(9\right)[/tex]
[tex]=522[/tex] cubic inches
Now volume of the small cubic prism [tex]=(Length)^3=\left(\frac{1}{2}\right)^3=\frac{1}{8}[/tex]
Then number of cubes that can fit into the right rectangular prism [tex]=\frac{522}{\left(\frac{1}{8}\right)}=522*8=4176[/tex]
Hence correct choice is D) 4176 unit cubes
A target with a diameter of 14cm has 4 scoring zones by concentric circles. The diameter of the center circle is 2 cm. The width of each ring is 2 cm. A dart hits the target at a random point. Find the probability that it will hit a point in the outer (yellow) ring
Answer:
[tex]48.98\%[/tex]
Step-by-step explanation:
we know that
The probability that it will hit a point in the outer (yellow) ring is equal to divide the area of the yellow ring by the total area of the target
step 1
Find the area of the yellow ring
[tex]A=\pi [7^{2} -5^{2}][/tex]
[tex]A=24\pi\ cm^{2}[/tex]
step 2
Find the total area of the target
[tex]A=\pi [7^{2}][/tex]
[tex]A=49\pi\ cm^{2}[/tex]
step 3
Find the probability
[tex]24\pi/49\pi=0.4898[/tex]
Convert to percentage
[tex]0.4898*100=48.98\%[/tex]
Answer:
0.38468
Step-by-step explanation:
To know the probability we need to know the area of the yellow zone and the area of the rest. So, the yellow circle (that contains white, red and blue circle) has a radius of 1+2+2+2=7. Then the area is
Area yellow= [tex]\pi r^{2}= \pi *7^{2}=49\pi.[/tex]
But, the yellow zone is yellow circle - blue circle.
Area blue = [tex]\pi r^{2}= \pi *(1+2+2)^{2}=\pi *5^{2}=25\pi.[/tex]
Then, the yellow zone will be [tex]49\pi-25\pi=24\pi.[/tex]
Area target= 14*14 = 196.
So, the probability is the yellow zone divided by the target (total area):
P = [tex]\frac{24\pi}{196}= \frac{6\pi}{49}= 0.38468.[/tex]
Figure 1 is a square pyramid. Figure 2 is a right triangular prism.
Complete the following statement about Figures 1 and 2.
The surface area of Figure 1 is ___ square centimeters ___ than the surface area of Figure 2.
Answer:
the answer is
The surface area of Figure 1 is 10.2 square centimeters Less than the surface area of Figure 2.
Step-by-step explanation:
Figure 1
area of a square = s2
=9squared
=81 sq cm
area of triangle = 1/2 bh
=1/2 (9cm) (14cm)
=63 sq. cm
find surface area
SA = 81 sq. cm + 4(63 sq. cm)
SA = 81 sq. cm + 252 sq. cm
SA = 333 sq. cm
Figure 2 Calculation
area of rectangle = lw
a = (12cm) (8 cm)
a = 96 sq. cm
area of triangle = 1/2 bh
=1/2 (8 cm) (6.9 cm)
= 27.6 sq. cm
total surface are of figure 2
SA = 3 (96 sq.cm) + 2 (27.6 sq. cm)
SA = 288 sq. cm + 55.2 sq. cm
SA = 343.2 sq. cm
find the difference between figure 1 and figure 2
343.2 sq. cm - 333 sq. cm = 10.2 sq. cm
Final answer:
We cannot complete the statement definitively about the surface area comparison between the square pyramid and the triangular prism without specific measurements. However, if we knew the dimensions, we could use the principle that surface area scales with the square of the linear dimensions to compare the two.
Explanation:
To complete the statement about the surface areas of Figure 1 (a square pyramid) and Figure 2 (a right triangular prism), we need to consider how areas scale with the dimensions of the shapes. Salviati's example illustrates that surface areas scale with the square of the linear dimensions, which is an important concept in geometry. Applying this concept to two triangles where one is larger than the other with linear dimensions twice as long, the larger triangle will have an area four times greater (area scales with the square of the linear dimensions).
Correct solution #1: Since the larger triangle's sides are twice as long, its area is 22 = 4 times more than the smaller triangle. If we applied similar reasoning and knew the dimensions of Figure 1 and Figure 2, we could compare their surface areas. However, with the provided information, we cannot definitively complete the given statement about the surface area of the pyramid relative to the prism without the specific measurements of each figure.
By understanding that the surface area of shapes scales with the square of their dimensions and using examples like cutting the larger triangle into four smaller ones (correct solution #2), we can tackle the surface area comparison confidently, provided we have the necessary dimensions.
what is 7pounds equal to in ounces
Answer: that would be 112 oz
Step-by-step explanation:
Answer:
I believe the correct answer is 112 Ounces
Step-by-step explanation:
: 16 (1 lb = 16 oz)
which means you would do 7 times 16
How many times greater is the value of 0.03 than the value of 0.003
Answer:
The answer .03 is 10 times greater than .003
Step-by-step explanation:
.003 x 10= .03
Final answer:
The value of 0.03 is ten times greater than the value of 0.003. This is evident by observing that 0.03 is expressed as 3 x 10^-2 while 0.003 is expressed as 3 x 10^-3, showing 0.03 is one decimal place to the left of 0.003.
Explanation:
The value of 0.03 is ten times greater than the value of 0.003. This conclusion is reached by observing the placement of the decimal point. For each power of ten we move to the right, the number becomes 1/10 the size of the previous number. Conversely, moving one place to the left (making the number ten times bigger), we increase the value of the number by a factor of 10.
Expressing these numbers with negative exponents, we have:
0.03 as 3.0 x 10-2 (three and zero tenths times ten to the negative second power)0.003 as 3.0 x 10-3 (three and zero tenths times ten to the negative third power)As illustrated above, since 10-3 is one factor of 10 smaller than 10-2, the value 0.03 is ten times greater than 0.003.
On May 9, 2014 Jason made a deposit of $650.00. What is his balance after this transaction?
A) $540.28
B) $832.45
C) $1190.28
D) $1548.11
Answer:
What did he have before?
Step-by-step explanation:
A is the correct answer
ASAP
How to do
With steps
Thx
Answer:
Angle A measures 180° - (24° + 55°) = 180° - 79° = 101°.
Angle x measures 360° - 101° = 259°.
A painter needs a piece of glass to protect a painting. He is also putting wooden strips around the perimeter to make a frame for the painting. The painting is 85 centimeters by 62 centimeters. How many square centimeters of glass does he need to cover the area of the painting?
Answer:
5270cm^2
Step-by-step explanation:
85 * 62 = 5270
It says it is asking for square centimeters and area, so use the formula for the area of a rectangle (b * h).
Answer: 5270cm^2
Step-by-step explanation: 85 * 62 = 5270
Lance is 5 feet tall. His shadow is 8 feet long. At the same time of day trees shadow is 32 feet long. What is the height of the tree in feet.
Set u a ratio of height over shadow:
Lance = 5 feet tall / 8 foot shadow
Tree = X feet tall / 32 foot shadow.
Set the ratios equal to each other and solve for X:
5/8 = x/32
Cross multiply:
8x = 160
Divide both sides by 8:
x = 160/8
x = 20
The tree is 20 feet tall.
Zack buys some oranges from a store. The oranges cost $4.00 for 2 pounds. He wants to buy more fruit, but at the same price per pound as the oranges. Which of the following fruits could Zack buy?
A.
bananas at $2.00 for 5 pounds
B.
strawberries at $9.00 for 3 pounds
C.
peaches at $6.00 for 3 pounds
D.
blueberries at $8.00 for 2 pounds
For this case, I should find the unit cost per pound of orange.
[tex]\frac {4} {2} = 2 \frac {dollars} {libra}[/tex]
Zack wants to buy at the same price per pound.
Then, you can buy peaches:
[tex]\frac {6} {3} = 2 \frac {dollars} {pound}[/tex]
Answer:
Option C
Peaches at $ 6.00 for 3 pounds
39/51 change to lowest terms
Answer:
As a proper fraction - 39/51 = 13/17
As a decimal number: 39/51 ≈ 0.76
As a percentage: 39/51 ≈ 76.47%
Step-by-step explanation:
Calculate the greatest (highest) common factor (divisor), gcf (gcd).
13/17 =
13 ÷ 17 =
0.764705882353 ≈
0.76
By precentage
0.764705882353 =
0.764705882353 × 100/100 =
76.470588235294/100 =
76.470588235294% ≈
76.47%
The following equation is being multiplied by the LCD. Complete the multiplication to eliminate the denominators
x+2/3x - 1/x-2 = x-3/3x
(3x)(x-2) [x+2/3x - 1/x-2] = (3x)(x-2) [x-3/3x]
The resulting equation is
x+2-1 = x-3
3x(x+2)-(x-2) = x-3
(x-2)(x+2)-1 = (x-3)(x-2)
(x-2)(x+2)-3x=(x-2)(x-3)
After multiplying by the LCD, the denominators are eliminated, resulting in the equation (x-2)(x+2) - 3x = (x-2)(x-3). Further simplifying this equation, we obtain x^2 - 3x - 4 = x^2 - 5x + 6 which can then be solved with algebraic methods.
Explanation:To solve the given equation by multiplying each term by the lowest common denominator (LCD), which is 3x(x-2), we need to eliminate the fractions first.
The given equation is:
(x+2)/(3x) - 1/(x-2) = (x-3)/(3x)
After multiplying each term in the equation by the LCD, we have:
3x(x-2) * ((x+2)/(3x)) = (x-2)(x+2)3x(x-2) * (-1/(x-2)) = -3x3x(x-2) * ((x-3)/(3x)) = (x-2)(x-3)Now, we can write the new equation without denominators:
(x-2)(x+2) - 3x = (x-2)(x-3)
Next, we simplify it:
x^2 + 2x - 2x - 4 - 3x = x^2 - 3x - 2x + 6
x^2 - 3x - 4 = x^2 - 5x + 6
This equation can now be simplified or solved using algebraic methods such as combining like terms or moving all terms to one side in preparation for factoring or applying the quadratic formula.
Learn more about Multiplying by LCD here:https://brainly.com/question/29186814
#SPJ3
Answer:
(x-2)(x+2) - 3x = (x-2)(x-3)
Step-by-step explanation:
Chuck can afford a $490-per-month car payment, and he's interested in either
a convertible, which costs $28,700, or a sports car, which costs $29,200. If he
is being offered a 6-year car loan with an APR of 6%, compounded monthly,
which car can Chuck afford?
Answer:
Chuck can afford both the convertible and sports car APEX
Step-by-step explanation:
Answer:
We can say that Chuck can afford both the cars.
Step-by-step explanation:
The EMI formula is :
[tex]\frac{p*r*(1+r)^{n} }{(1+r)^{n}-1 }[/tex]
Case 1:p = 28700
r = 6/12/100=0.005
n = 6*12=72
Putting the values in the above formula, we get:
[tex]\frac{28700*0.005*(1.005)^{72} }{(1.005)^{72}-1 }[/tex]
Monthly payment is = $475.67
Case 2:p = 29200
r = 6/12/100=0.005
n = 6*12=72
Putting the values in the above formula, we get:
[tex]\frac{29200*0.005*(1.005)^{72} }{(1.005)^{72}-1 }[/tex]
Monthly payment is = $483.96
We can see that in both the cases, the monthly payments or EMI's are less than $490.
Therefore, we can say that Chuck can afford both the cars.
Kira's Bagel Shop recently sold 18 bagels, of which 6 were blueberry bagels. What is the experimental probability that the next bagel sold will be a blueberry bagel?
108 is the number of blueberry baglels
You save 3 ,260.00 in a savings account earning a 3.55% APR compounded monthly. How much is the total interest earned by the end of the third month?
The answer will be $29.02. :)
Answer:
$29.02.
Step-by-step explanation:
We have been given that you save 3 ,260.00 in a savings account earning a 3.55% APR compounded monthly. We are asked to find the total interest earned by the end of the third month.
We will use compound interest formula to solve our given problem.
[tex]A=P(1+\frac{r}{n})^{nt}[/tex], where,
A = Amount of interest after t years,
P = Principal amount,
r = Annual interest rate in decimal form,
n = Number of periods interest is compounded per year,
t = Time in years.
[tex]3.55\%=\frac{3.55}{100}=0.0355[/tex]
[tex]\text{3 months}=\frac{3}{12}\text{ year}=\frac{1}{4}\text{ year}[/tex]
Upon substituting our given values in above formula, we will get:
[tex]A=3,260(1+\frac{0.0355}{12})^{12\times \frac{1}{4}}[/tex]
[tex]A=3,260(1+0.002958333)^{3}[/tex]
[tex]A=3,260(1.002958333)^{3}[/tex]
[tex]A=3,260*1.00890128109888[/tex]
[tex]A=3289.0181763823\approx 3289.02[/tex]
Now, we will subtract principal amount from final amount to find amount of interest.
[tex]\text{Amount of interest}=3289.02-3260[/tex]
[tex]\text{Amount of interest}=29.02[/tex]
Therefore, you will earn am amount of $29.02 by the end of the third month.
5 college students were asked how many hours of sleep did they get at night on the average the responses were a 7 hours 9 hours 5 hours 6 hours and 8 hours what is the average amount of hours of sleep do college students got in a night
7 Hours on Average
add up all the hours and you get 35
then divide 35 by the number of given hours which is 5
35/5 = 7
so the average amount of hours slept was 7
Answer:
7 hours
Step-by-step explanation:
To find this average, add up the five data points given and divide your result by five (5):
(7 + 9 + 5 + 6 + 8) / 5 = 35 / 5 = 7
This group of students averaged 7 hours of sleep per night.
Jeremy says that if you translate, rotate, or reflect a polygon, the area of the image is the same as the area of the original figure. Do you agree or disagree? Explain your choice.
Answer:
yes
Step-by-step explanation:
as long as the polygon is not dilated or the size of the polygon is not changed in any way, the area should stay the same.
Match the following reasons with the statements given. Given: R = Q AS = AT Prove: RS = QT. 1. ∠R = ∠Q, AS = AT Given 2. ∠5 = ∠6 Base ∠'s of isosceles triangle are = 3. ∠4, ∠5 are supplementary and ∠6, ∠7 are supplementary Exterior sides in opposite rays 4. ∠4 = ∠7 CPCTE 5. Triangle RAS congruent to Triangle QAT Two ∠'s supplementary to equal ∠'s are = 6. RS = QT AAS
∠R = ∠Q, AS = AT Given
∠5 = ∠6 Base ∠'s of isosceles triangle are =
∠4, ∠5 are supplementary and ∠6, ∠7 are supplementary Exterior sides in opposite rays
∠4 = ∠7 Two ∠'s supplementary to equal ∠'s are =
Triangle RAS congruent to Triangle QAT AAS
RS = QT CPCTE
Answer:
∠R = ∠Q, AS = AT Given
∠5 = ∠6 Base ∠'s of isosceles triangle are =
∠4, ∠5 are supplementary and ∠6, ∠7 are supplementary Exterior sides in opposite rays
∠4 = ∠7 Two ∠'s supplementary to equal ∠'s are =
Triangle RAS congruent to Triangle QAT AAS
RS = QT CPCTE
Step-by-step explanation:
When you divide a unit fraction by a whole number number, will the quotient be greater than or less than the unit fraction?
Answer:
it will be less than
Step-by-step explanation:
Answer:less than
Step-by-step explanation:
Match the people with their accomplishments. 30 points!!
Answer:
View the picture please!
Step-by-step explanation:
mountain bike tire completes 20 revolutions and travels 136 feet. Rounded to the nearest inch, what is the diameter of the bike’s tire?
Answer: 26in
s=r*theta
r=s/theta
d=r*2
136ft=r*40pi
r=136/40pi=1.082ft
d=1.082*2=2.1645ft*(12in/1ft)=25.97in
Rounded to nearest in is 26in diameter
The diameter of the bike's tire is calculated by dividing the total distance traveled by the number of revolutions to find the circumference and then dividing the circumference by pi (π) to find the diameter, which is approximately 26 inches.
Explanation:To find the diameter of the bike’s tire, given that it completes 20 revolutions and travels 136 feet, we can use the relationship between the circumference of a circle (in this case, the tire) and its diameter.
First, we calculate the circumference of the tire by dividing the total distance traveled by the number of revolutions:
Circumference = Total Distance ÷ Number of Revolutions
Total Distance = 136 feet (1 foot = 12 inches, so convert feet to inches for precision)
Total Distance in inches = 136 feet × 12 inches/foot = 1632 inches
Circumference = 1632 inches ÷ 20 = 81.6 inches
Now, we use the circumference to find the diameter:
Circumference = π × Diameter
Diameter = Circumference ÷ π
Diameter ≈ 81.6 inches ÷ π ≈ 26 inches
Therefore, the diameter of the bike’s tire, rounded to the nearest inch, is approximately 26 inches.
A pre-image point is rotated 90° clockwise. If the pre-image point had the coordinates (3, -5), what are the coordinates of its image point?
(-5, -3)
(5, 3)
(-3, 5)
(-3, -5)
A pre-image point is rotated 90° clockwise. If the pre-image point had the coordinates (3, -5), what are the coordinates of its image point?
(-5, -3)
(5, 3)
(-3, 5)
(-3, -5)
Next Question
Ask for help
Turn it in
(5,3)
Explanation1. Determine the rule for this rotation
(x,y) ---> (-y,x)
2. Plug in
(3, -5) ----> (5,3)
Answer
(5,3)
Answer:
( -5, -3) .
Step-by-step explanation:
Given : A pre-image point is rotated 90° clockwise. If the pre-image point had the coordinates (3, -5).
To find : what are the coordinates of its image point.
Solution : We have given that
Parent coordinates (3, -5)
If the point is rotated 90° clockwise.
By the rotation rule of 90° clockwise (x ,y) →→ ( y , -x) .
Then (3 ,-5) →→ ( -5, -3)
Therefore, ( -5, -3) .
I don't know math can u help me please
Angles are suck
Answer:
M<FDE = 360 degrees
Step-by-step explanation:
120 degrees is supplementary to x which makes it 120. 120+120=240 degrees. angle x and angle d = 120+120 which makes it 360 degrees.
M<ADE however, is 110+120=280, 360-280=80 degrees which is 110+120+80=360 degrees. So, M<ADE is 360 degrees and it is equal to M<FDE which is also 360 degrees.
All of them are equal. The sum of the figure is 720 Degrees.
Answer:
∠FDE = 130°
Step-by-step explanation:
Since BC and DE are parallel lines, then
∠BDE = ∠ABC = 110° ( corresponding angles are congruent )
The sum of the angles round a point = 360°, thus
∠BDE + ∠BDF + ∠FDE = 360 , hence
110 + 120 + x = 360
230 + x = 360 ( subtract 230 from both sides )
x = 130
Hence x = ∠FDE = 130°
One pallet can store 15^5 water bottles. A stock room receives 15^13 water bottles.
Enter the number of pallets needed to store all the water bottles the stock room received.
___pallets
Answer:
3 pallets
Step-by-step explanation:
Divide to find the amount of pallets:
Subtract Exponents to divide
15^13 / 15^5 = 13 - 5 = 8 - 5 = 4 (subtracted 2 times)
You need three to store ALL the water
The stock room will need [tex]15^8[/tex] pallets to store the received [tex]15^13[/tex] water bottles since each pallet can store [tex]15^5[/tex] water bottles and we divide the total number by the pallet capacity.
To calculate the number of pallets needed to store all the water bottles the stock room received, we need to divide the total number of water bottles by the number of bottles a single pallet can hold.
The pallet can store 155 water bottles, and the stock room receives 1513 water bottles. By dividing the total number of bottles by the capacity of a pallet, the calculation is:
1513 ÷ 155 = 1513-5 = 158
Therefore, the stock room will need 158 pallets to store all the received water bottles.
The following table represents a quadratic function which of the following are true of the graph hat represents the same quadratic function select all that apply
Answer:
Step-by-step explanation:
The graph has a relative minumum. TRUE Actually, I'd call it an absolute minimum, since 5 is the smallest y value and the graph opens up.
The graph shown has a vertex at (0, 5) TRUE. This point is also the absolute minimum of the function.
The graph opens up. TRUE
The graph has neither one nor two x-intercepts. The graph never crosses or touches the x-axis.
Answer:
A,B,C,F
Step-by-step explanation:
everything above was right except that there were more answers! For Algebra Nation the photo is incomplete and doesnt show the last two questions. I just took the test
Write the equation in exponential form. Log 4 1/16 =-2
Answer:
see explanation
Step-by-step explanation:
Using the rule of logarithms
• [tex]log_{b}[/tex] x = n ⇔ x = [tex]b^{n}[/tex]
Hence
with b = 4 and n = - 2
[tex]log_{4}[/tex] [tex]\frac{1}{16}[/tex] = - 2, then
[tex]\frac{1}{16}[/tex] = [tex]4^{-2}[/tex] ← in exponential form
ANSWER
The exponential form is
[tex] \frac{1}{16} = {4}^{ - 2} [/tex]
EXPLANATION
The given logarithm is
[tex] log_{4}( \frac{1}{16} ) = - 2[/tex]
We want to write the given logarithm in exponential form:
We take the antilogarithm of both sides to obtain:
[tex] {4}^{log_{4}( \frac{1}{16} )} = {4}^{ - 2} [/tex]
We simplify the left hand side to obtain:
[tex] \frac{1}{16} = {4}^{ - 2} [/tex]
Hence the exponential form is
[tex] \frac{1}{16} = {4}^{ - 2} [/tex]
Mrs. Jenkins just finished grading her math tests. The average score on her test was 93%. However, she forgot to grade Billy's paper. Billy scored 80% on the test. What is going to happen to the class average, once she includes Billy's score?
A.
The class average will stay the same.
B.
The class average will go up.
C.
The class average will go down.
D.
There is not enough information.
Including Billy's score of 80% will lower the class average from 93% because his score is below the initial average.
Explanation:When including Billy's test score of 80% into the class average that was previously 93%, the class average will definitely go down. This is because Billy's score is lower than the class average, so when it is factored into the overall calculation, it will decrease the average. Hence, the correct answer to the question is: C. The class average will go down.