Calculating the number of subway riders who took between 30 and 43 trips involves finding z-scores for these trip numbers, looking up the corresponding probabilities in the normal distribution table, and multiplying the difference by the total population of riders.
Explanation:The question relates to normal distribution and requires calculating the number of individuals in a given population that fall within a specific range of values. The population in question is 800,000 subway riders whose number of trips are normally distributed with a mean (μ) of 56 and a standard deviation (σ) of 13. The task is to find out how many riders took between 30 and 43 trips last January.
To solve this, we first find the z-scores for the values 30 and 43. The z-score is calculated by subtracting the mean from the value and dividing the result by the standard deviation. This will give:
Z for 30 = (30 - 56) / 13 = -2Z for 43 = (43 - 56) / 13 = -1Next, we look up these z-scores in a standard normal distribution table to find the probabilities corresponding to these z-scores. The difference between these probabilities will give us the proportion of riders who took between 30 and 43 trips. Finally, we multiply this proportion by the total population of riders (800,000) to get the number of riders. Assume that the probabilities from the z-table are 0.0228 for z = -2 and 0.1587 for z = -1.
The calculation would be approximately:
Number of riders = 800,000 * (0.1587 - 0.0228) = 800,000 * 0.1359 = 108,720 riders
Ciara solved the exponential equation 3x+1 = 15 and her work is shown below. What is the first step she did incorrectly?
Step 1: log 3x+1 = log15
Step 2: (x + 1)log 3 = log15
Step 3: log3 = log 15 over x plus 1
Step 4: 0.477121 = 1.176091 over x plus 1
Step 5: 0.477121(x + 1) = 1.176091
Step 6: x + 1 = 1.176091 over 0.477121
Step 7: x + 1 = 2.464975
Step 8: x = 1.464975
(I think it is Step 3)
Sam and jesse can wash five cars each hour they work for seven hours each day over two days how many cards did sam and jesse wash?
Sam and Jesse wash a total of 70 cars over two days, by washing five cars each hour for seven hours each day.
Explanation:Sam and Jesse work together to wash cars. They can wash five cars each hour, and they work for seven hours each day. Since they do this over the course of two days, we need to calculate the total number of cars they wash in this period.
First, we find out how many cars they can wash in one day by multiplying the number of cars they can wash in an hour by the number of hours they work:
5 cars/hour * 7 hours/day = 35 cars/dayNext, since they work for two days, we multiply the number of cars washed in one day by two:
35 cars/day * 2 days = 70 carsSam and Jesse wash a total of 70 cars over the two days.
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What is the slope of the line joining (5, 9) and (−2, 9)?
A. -7/4
B.-4/7
C.0
D.No slope
what are three equivalent fractions for 80/100 ...?
Three equivalent fractions for [tex]\( \frac{80}{100} \) are \( \frac{4}{5} \), \( \frac{160}{200} \), and \( \frac{400}{500} \)[/tex].
To find three equivalent fractions for [tex]\( \frac{80}{100} \)[/tex], we can simplify the fraction by dividing both the numerator and denominator by their greatest common divisor (GCD), which is 20 in this case.
1. Divide both the numerator and denominator by 20:
[tex]\[ \frac{80 \div 20}{100 \div 20} = \frac{4}{5} \][/tex]
So, [tex]\( \frac{80}{100} \)[/tex] is equivalent to [tex]\( \frac{4}{5} \)[/tex].
2. Multiply both the numerator and denominator by the same non-zero integer:
[tex]\[ \frac{80 \times 2}{100 \times 2} = \frac{160}{200} \][/tex]
So, [tex]\( \frac{80}{100} \) is also equivalent to \( \frac{160}{200} \)[/tex].
3. Similarly, we can multiply both the numerator and denominator by another non-zero integer:
[tex]\[ \frac{80 \times 5}{100 \times 5} = \frac{400}{500} \][/tex]
So, [tex]\( \frac{80}{100} \) is also equivalent to \( \frac{400}{500} \)[/tex].
If two pounds of meat will serve 5 people, how many pounds will be needed to serve 13 people?
To convert from pounds to ounces, multiply the number of pounds by the unit equivalence of 1 pound = 16 ounces.
Conversion from pounds to ounces:
First, find the unit equivalence: 1 pound = 16 ounces.
Next, multiply the number of pounds by the unit equivalence. Thus, 5 pounds x 16 equals 80 ounces.
A children's book has dimensions 20 cm by 24 cm.
What scale factor should be used to make an enlarged version that has dimensions 25 cm by 30 cm?
A. 5
B. 1.5
C. 1.25
D. 0.8
Answer:
We should use C. 1.25
Step-by-step explanation:
We know that the children's book dimensions are 20 cm x 24 cm
We need to find a scale factor (which is a number) that will turn the dimensions 20 cm x 24 cm ⇒ 25 cm x 30 cm
We can write :
(20 cm) . a = 25 cm
Where ''a'' is the scale factor.
Solving for a :
[tex](20cm).a=25cm\\a=\frac{25cm}{20cm}=1.25 \\a=1.25[/tex]
This result is reasonable because the scale factor won't have units
A scale factor of 1.25 turns 20 cm ⇒ 25 cm
We can use the another dimension to verify :
(24 cm) . a = 30 cm
(24 cm) . (1.25) = 30 cm
30 cm = 30 cm
The scale factor is option C. 1.25
The inverse of the function f(x) = 1/2x + 10 is shown.
h(x) = 2x – ?
What is the missing value?
Answer:
d. 20
Step-by-step explanation:
Replace the x and y values in the equation
(y = 0.5x + 10) to (x = 0.5y + 10)
Now, solve for the y value in the new equation. You'll get y = 2x + 20.
So, the intercept of the inverse function is 20.
ricardo has a bag of mixed fruit snacks. in the bag, there are 8 cherry fruit snacks and 12 strawberry fruit snacks. what is the ratio of strawberry to cherry?
a rectunglar pool is 7ft wide. it is 3 time as long as it is wide
All real numbers n that are less than -3
The set of all real numbers n that are less than -3 can be represented as: [tex]\[ \{ n \mid n < -3 \} \][/tex]
The set of real numbers less than -3 encompasses an infinite range of values extending to the left of -3 on the number line. These numbers are characterized by being smaller than -3, denoted as ( n < -3 ). In interval notation, this set is represented as (-∞, -3), indicating that it includes all real numbers from negative infinity up to, but not including, -3.
This set is unbounded, as there is no limit to how far left the numbers extend, encompassing an infinite continuum of values that are progressively smaller than -3.
Tarriq begins to solve the equation 50 + 2x = –190.
50 + 2x = –190
50 – 50 + 2x = –190 – 50
2x = –240
To finish solving the equation using the multiplication property of equality, which factor must Tarriq use?
A)-2
B)-1/2
C)1/2
D)2
Tarriq must use "2" as the Multiplication Property of equality.
What is the Multiplication Property of Equality?The Multiplication Property of Equality for any numbers a, b, and c, If we multiply both sides of an equation by the identical number, we always have equivalency.
Rearrange unfamiliar terms to the left side of the equation then
2x = -190 - 50
Calculate the sum or difference
2x = -240
Divide both sides of the equation by the coefficient of variable 2, and we get
x = -240 [tex]$ \div[/tex] 2
Calculate the product or quotient then we get
x = -120
Therefore, the correct answer is option D) 2.
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Tarriq must use factor C) 1/2, as this represents dividing both sides of the equation by 2 to isolate x, resulting in x = –120.
To finish solving the equation 2x = –240 using the multiplication property of equality, Tarriq must divide both sides of the equation by 2, which is the coefficient of x.
This step can be shown as:
2x / 2 = –240 / 2
The division property of equality allows us to simplify by canceling out the 2s on the left, resulting in:
x = –240 / 2
Therefore, x equals:
x = –120
This shows that the factor Tarriq must use to finish solving the equation is C) 1/2 since that represents the inverse operation of multiplying by 2.
-x^2=23 in standard form
Convert the function into intercept form. Show your work. y=-x^2+5x+36
If f(x) = 5x + 40, what is f(x) when x = –5?
A. -9
B. -8
C. 7
D. 15
Answer:
D) 15
Step-by-step explanation:
The value of the function f(x) = 5x + 40 at x = -5 will be 15. Then the correct option is D.
What is a function?A statement, principle, or policy that creates the link between two variables is known as a function. Functions are found all across mathematics and are required for the creation of complex relationships.
The function is given below.
f(x) = 5x + 40
The value of the function f(x) = 5x + 40 at x = -5, then the value of the function will be
f(-5) = 5 (-5) + 40
f(-5) = - 25 + 40
f(-5) = 15
Then the value of the function f(x) = 5x + 40 at x = -5 will be 15.
Then the correct option is D.
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If line segment AB = 12 feet, what is the length of line segment AC?
Select one of the options below as your answer:
A.
6 feet
B.
10 feet
C.
12 feet
D.
24 feet
PLEASE HELP!! the measures of two complementary angles are in the ratio 2:3. What is the measure of the smaller angle?
An equation for a line in the plane allows you to find the x- and y-coordinates of any point on that line.
A. True
B. False
An equation for a line in the plane allows you to find the x- and y-coordinates of any point on that line.
Explanation:The statement is True.
An equation for a line in the plane, such as y = mx + b, allows you to find the x- and y-coordinates of any point on that line. The x-coordinate can be found by substituting a given y-value into the equation and solving for x. Similarly, the y-coordinate can be found by substituting a given x-value into the equation and solving for y.
Answer: TRUE!!!!!
Step-by-step explanation:
trust me
What is v in this formula v=3u 5t if u=5.1 and t=27.3 v?
Parabola: The _____ value looks like the bottom of a valley. ...?
Two cars, car X and car Y , start moving from the same point P on a cross intersection. Car X is travelling east and car Y is travelling north. Some time later car X is 60 km east of point P and travelling in an easterly direction at 80 km/h and car Y is 80 km north of point P and travelling in a northerly direction at 100 km/h. How fast is the distance between car X and car Y changing?
Conver the equation y=2 to polar form. Then solve the resulting equation for r.
Thanks :)
Elena has 32 hair ties. Melanie has 8 hair ties the ratio of elena's hair ties to Melanie's hair ties is
The new ratio of Elena’s hair ties to Melanie’s hair ties is 8 : 3.
Given that Elena has 32 hair ties and Melanie has 8 hair ties, let’s analyze the situation:
Initial Ratio:
The ratio of Elena’s hair ties to Melanie’s hair ties is: [ \text{Elena : Melanie} = 32 : 8 = 4 : 1 ]
Melanie Gets 4 More Hair Ties:
After Melanie receives 4 additional hair ties, her total becomes: [ \text{Melanie’s new total} = 8 + 4 = 12 ]
New Ratio:
Now, let’s find the new ratio of Elena’s hair ties to Melanie’s hair ties: [ \text{Elena : Melanie} = 32 : 12 = 8 : 3 ]
Therefore, the new ratio of Elena’s hair ties to Melanie’s hair ties is 8 : 3.
Complete question:
Elena has 32 hair ties. Melanie has 8 hair ties. The ratio of Elena’s hair ties to Melanie’s hair ties is : 1. If, Melanie gets 4 more hair ties, the new ratio of Elena’s hair ties to Melanie’s hair ties is 8 :
Which is the safest way to invest money??
Invest in more than one type of investment.
9% percent are in the band. the band has 180 members.how many people are in school
The correct answer is that there are 2000 people in the school.
To solve this problem, we can set up a proportion based on the information given. We know that 9% of the school's population is in the band, and the band has 180 members. We want to find the total population of the school, which we will denote as [tex]\( P \)[/tex].
The proportion can be written as:
[tex]\[ \frac{9}{100} = \frac{180}{P} \][/tex]
Now, we can solve for [tex]\( P \)[/tex] by cross-multiplying:
[tex]\[ 9P = 180 \times 100 \][/tex]
Divide both sides by 9 to isolate [tex]\( P \)[/tex]:
[tex]\[ P = \frac{180 \times 100}{9} \][/tex]
Simplify the right side of the equation:
[tex]\[ P = \frac{18000}{9} \][/tex]
[tex]\[ P = 2000 \][/tex]
Therefore, the total population of the school is 2000 people. This matches the correct answer given in the options.
. Zalia meets her friend at the science museum to see a special exhibition. The admission to the museum is $12.50 plus tax. Zalia pays for herself and her friend. They have lunch at the museum’s cafe. Zalia has a sandwich for $5.95, an apple for $1.25 and a drink for $1.69. She is charged tax and also tips her server 15%. If tax is 7.25%, how much did Zalia pay all total for her day at the science museum?
a.
$41.43
b.
$37.68
c.
$36.35
d.
$24.27
The total comes to $37.67, so the closest answer is (b) $37.68.
We will calculate how much Zalia paid for her day at the science museum including admission fees, lunch, and the tax and tip for both of these.
Firstly, let's calculate the total cost of admission for Zalia and her friend:
Admission for one person: $12.50
Admission for two people: $12.50 x 2 = $25.00
Now, let's find the total cost of Zalia's lunch:
Sandwich cost: $5.95
Apple cost: $1.25
Drink cost: $1.69
Total lunch cost before tax and tip: $5.95 + $1.25 + $1.69 = $8.89
Next, we add the tax:
Tax for admission: $25.00 x 7.25% = $1.81
Tax for lunch: $8.89 x 7.25% = $0.64
Total tax: $1.81 + $0.64 = $2.45
Now, we calculate the tip for the lunch:
Tip: $8.89 x 15% = $1.33
Finally, add everything up to get the total amount Zalia paid:
Total cost without tax and tip: $25.00 + $8.89 = $33.89
Total tax and tip: $2.45 + $1.33 = $3.78
Grand total: $33.89 + $3.78 = $37.67
Examining the provided options, we can see that the closest amount to our calculation is $37.68, considering the possibility of a rounding difference in the final tax and tip calculations. Thus, the correct answer is (b) $37.68.
Which shows the correct substitution of the values a, b, and c from the equation 0 = 4x2 + 2x – 1 into the quadratic formula below?
Quadratic formula: x =
Answer:
[tex]x=\frac{-2\pm \sqrt{(2)^{2}-4(4)(-1)}}{2(4)}[/tex] is the answer.
Step-by-step explanation:
Given quadratic equation is 4x²+ 2x - 1 = 0
To find the solution of the equation we use the quadratic formula
[tex]x=\frac{-b\pm \sqrt{b^{2}-4ac}}{2a}[/tex]
Now we put the values of a = 4, b = 2 and c = (-1)
Therefore, quadratic formula for the equation given will be
[tex]x=\frac{-2\pm \sqrt{(2)^{2}-4(4)(-1)}}{2(4)}[/tex]
Andrea borrowed 2,240 at 15% apr for 18 months. how much interest will she pay?is the answer $336
Answer:
No, the answer is not $ 336
The interest that she will pay is $ 504.
Step-by-step explanation:
Given : Andrea borrowed 2,240 at 15% apr for 18 months.
We have to calculate the interest will she pay.
Using formula for Simple interest.
[tex]SI =P\times r\times t[/tex]
Where P is principal amount
r is rate of interest
t is time period.
Given : P = $ 2240
t = 18 months
In years , [tex]\frac{18}{12}[/tex]
r = 15% = 0.15
Substitute, we have,
[tex]SI=2240\cdot0.15\cdot\frac{18}{12}[/tex]
Simplify, we have,
SI = 504
Thus, The interest that she will pay is $ 504.
No, the answer is not $ 336
Andrea will pay $504 in interest on a loan of $2,240 at 15% APR over 18 months, not $336. The calculation involves converting the loan duration into years and applying the formula for simple interest.
To determine how much interest Andrea will pay on a loan of $2,240 at 15% APR for 18 months, we first need to understand that APR (Annual Percentage Rate) is the interest rate for a whole year (annual), rather than just a monthly fee or rate. Since APR is annual but our loan term is in months, we convert the duration into years to match the APR's annual nature. 18 months is equivalent to 1.5 years. Therefore, the interest calculation would be as follows:
Principal (the amount borrowed) = $2,240
Rate (APR) = 15%
Time = 1.5 years
Interest = Principal × Rate × Time
Interest = $2,240 × 15% × 1.5 = $2,240 × 0.15 × 1.5
Interest = $504
Therefore, Andrea will pay $504 in interest, not $336 as presumed. It's essential to accurately convert the time to years when dealing with APR to ensure the calculation is correct.
Optimization. A rectangle is to have an area of 32 square cms. Find its dimensions so that
the distance from one corner to the mid point of a non-adjacent edge is a
minimum ...?
To optimize the dimensions of a rectangle with an area of 32 square cm such that the distance from one corner to the midpoint of a non-adjacent edge is minimized, one must use the Pythagorean theorem and calculus. The minimum distance occurs when the rectangle is a square with sides measuring 4√2 cm.
Assume the rectangle's dimensions are length L and width W, with the given area 32 cm2 such that LW = 32. To minimize the distance (D) from one corner to the midpoint of the non-adjacent edge, we can use the Pythagorean theorem, given by D = √(L2 + (W/2)²).
Since the area is fixed, W can be expressed as 32/L, and we can write D as a function of L. After substituting 32/L for W and differentiating with respect to L, we can find the minimum by setting the derivative equal to zero and solving for L.
The minimum distance is achieved when the rectangle is a square, with length and width both equal to √32, which simplifies to 4√2 cm, which is approximately 5.66 cm for both dimensions.
Samuel and Jason spend 3/4 of their combined earnings from Wednesday to buy a gift. How much do they spend? Is there enough left over from Wednesday's earnings to buy a card that costs $3.25? Explain.
Earnings:
Samuel - (12.5×0.40)
Jason - (7.1×0.40)
Answer:
they spend $ 5.88 to buy a gift but there is not enough money left to buy a card of $3.25
Step-by-step explanation:
The earnings form Wednesday of Samuel and Jason are:
Samuel earnings = 12.5x0.40 = $5
Jason earnings = 7.1x0.40 = $ 2.84
The combined earnings form Wednesday are:
Combined earnings = Samuel earnings + Jason earnings
Combined earnings= $5 + $ 2.84 = $ 7.84
The spended earnings are:
Spended earnings = combined earnings x ¾
Spended earnings = 7.84 x ¾ = $ 5.88
The left over is:
Left over = combined earnings – spended earnings
Left over = 7.84 – 5.88 = $ 1.96
So, they spend $ 5.88 to buy a gift but there is not enough money left to buy a card of $3.25
What is the sum of the first five terms of a geometric series with a1 = 20 and r = 1/4?
Answer: The required sum of first terms of the series is [tex]\dfrac{1705}{64}.[/tex]
Step-by-step explanation: We are given to find the sum of the first five terms of a geometric series with first term and common ratio as follows :
[tex]a_1=20~~~~~\textup{and}~~~~~r=\dfrac{1}{4}.[/tex]
We know that
the sum of first n terms of a geometric series with first term [tex]a_1[/tex] and common ratio r is given by
[tex]S_n=\dfrac{a(1-r^n)}{1-r}.[/tex]
Therefore, the sum of first 5 terms of the given geometric series is given by
[tex]S_5\\\\\\=\dfrac{a(1-r^5)}{1-r}\\\\\\=\dfrac{20(1-(\frac{1}{4})^5)}{1-\frac{1}{4}}\\\\\\=\dfrac{20\left(1-\frac{1}{1024}\right)}{\frac{3}{4}}\\\\\\=20\times\dfrac{4}{3}\times\dfrac{1023}{1024}\\\\\\=20\times\dfrac{341}{256}\\\\\\=\dfrac{5\times 341}{64}\\\\\\=\dfrac{1705}{64}.[/tex]
Thus, the required sum of first terms of the given geometric series is [tex]\dfrac{1705}{64}.[/tex]