You have 42,784 grams of a radioactive kind of curium. If its half-life is 18 years, how much will be left after 72 years?
Answer:
2,674.14 g
Step-by-step explanation:
Recall that the formula for radioactive decay is
N = N₀ e^(-λt)
where,
N is the amount left at time t
N₀ is the initial amount when t=0, (given as 42,784 g)
λ = coefficient of radioactive decay
= 0.693 ÷ Half Life
= 0.693 ÷ 18
= 0.0385
t = time elapsed (given as 72 years)
e = exponential constant ( approx 2.7183)
If we substitute these into our equation:
N = N₀ e^(-λt)
= (42,787) (2.7183)^[(-0.0385)(72)]
= (42,787) (2.7183)^(-2.7726)
= (42,787) (0.0625)
= 2,674.14 g
Final answer:
After 72 years, which corresponds to 4 half-lives of the curium with a half-life of 18 years, the remaining amount of a 42,784 gram sample would be 2,674 grams, as it halves every 18 years.
Explanation:
The question asks how much of a radioactive sample of curium, with an initial mass of 42,784 grams and a half-life of 18 years, will remain after 72 years. To answer this, we apply the concept of radioactive decay, which follows a geometric sequence where the quantity of a radioactive substance halves every half-life period.
In this scenario, 72 years consist of 4 half-lives (since 72 ÷ 18 = 4). Therefore, after each half-life, the mass of the curium would be reduced by half. Following the sequence:
After 18 years, half of the 42,784 grams would remain, which is 21,392 grams.
After 36 years, half of that would remain, becoming 10,696 grams.
After 54 years, again half of that would remain, so 5,348 grams.
Finally, after 72 years, halving once more, we would be left with 2,674 grams.
The amount of curium remaining after 72 years is 2,674 grams.
What is the measure of angle X?
Answer:
47 degrees
Step-by-step explanation:
The interior angles of a triangle always equal 180 degrees, so add the other angles together and subtract that from 180
31+102= 133
180-133=47
Answer:
47
Step-by-step explanation:
By coincidence, Leon's Obedience School trained the same number of dogs and cats last
week. The school teaches dogs in groups of 2 and cats in groups of 7. What is the smallest
number of cats the school could have had?
Answer:
14
Step-by-step explanation:
In this case LCM is needed and the LCM of 2and 7 is 14. I hope this helps.
Which graphic organizer correctly shows the relationship between the shapes?
Answer:
the correct one is the quadrilateral with the parallelogram in it the one in the bottom corner under w
Step-by-step explanation:
hope this helps have a great day
Bonito is selling T-shirts for $8 each for his school fundraiser. So far, he has sold 16 T-
shirts. How many more does he need to sell to reach his goal of $200 in sales?
Three of these equations solve for the number of T-shirts, l, he still needs to sell to
reach $200 in sales. Which equation does NOT?
Answer:
The equations that does fit would be 8x+128=200, 8x=72. I don't know your answer choices but these are the equations that does fit so read what I wrote :)
Step-by-step explanation:
The equation would be 8x = 200 but knowing that he has already sold 16T shirts it should be 8x + 16*8 = 200 -> 8x+128 = 200 or 8x = 72. so x would be 9.
what integer represents a loss of $20
In math, a loss of $20 is represented by the negative integer -20. The negative in front of the 20 represents the loss or decrement.
Explanation:In mathematics, integers are whole numbers that can be either positive, negative, or zero. When we talk about a loss or decrement of something, it's universally symbolized with a negative integer.
In case of a loss of $20, it is represented as -20, where the negative sign indicates the loss or subtraction of money.
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when Sami showed her mother her shape picture. Mrs. Harper decided she would glue the pieces
on a white mounting board and frame the puzzle so Sami could hang it in her room. The mounting
board is 12 inches by 15 inches and there will be a colored mat on top of the mounting board that
Trames the letter S, which will be placed in the center of the mat and board. The mat is 1.5 inches
on all sides.
zin
1. What is the area of each square?
Answer:
[tex]2.25\ in^{2}[/tex]
Step-by-step explanation:
Area of a square is given by
[tex]A=b*b=b^{2}[/tex]
Where A is area and b is the length of any side. This question has only one thing that is square in shape, the mat hence the question directly requires its area.
Given that the mat has square shape and has dimensions of 1.5 in each then the area will be
A=1.5*1.5=2.25 square inches
Therefore, the area is 2.25 square inches.
Answer:
Step-by-step explanation:
Solve by finding square roots.
5x² - 400
-13.5
-$2.52
-2/2, 2/2
-2/3,283
Answer:
See explanation
Step-by-step explanation:
Let the given equation be:
[tex]5 {x}^{2} - 400 = 0[/tex]
This implies that:
[tex]5 {x}^{2} = 400[/tex]
Divide through by 5 to get;
[tex] {x}^{2} = 80[/tex]
Take square root to obtain:
[tex]x = \pm \sqrt{80} [/tex]
This implies that
[tex]x = \pm4 \sqrt{5} [/tex]
[tex]x = - 4 \sqrt{5} \: or \: x = 4 \sqrt{5} [/tex]
Help plz and god bless you and grades
Find 30% of 70
a. 21
b. 36
c. 40
If it takes 8 hours for Sanya to build a fence, and it takes 6 hours for Sean to build the same fence, how long will it take them working together?
Answer:
3 3/7 hours
Step-by-step explanation:
(8×6)/(8+6) = 48/14 = 3 3/7 hours
1 3/4 - 2 + -4 3/4
What is the answer
Answer:
[tex]\frac{-19}{2}[/tex]
Step-by-step explanation:
[tex]\frac{5}{4}[/tex] + [tex]\frac{-43}{4}[/tex] = [tex]\frac{-19}{2}[/tex]
Simplify 5a-2(-3a +b).
Steps to solve:
5a - 2(-3a + b)
~Distribute
5a + (-2 * -3a) + (-2 * b)
~Simplify
5a + 6a - 2b
~Simplify
11a - 2b
Best of Luck!
Norma has 9 pies to divide among 4 friends. How many pies will each friend receive if all of the pies must be used and can be divided into smaller parts? A 2/9 pie B. 4/9 pie C. 1 1/4 pies D. 2 1/4 pies
Answer:
D. 2 1/4
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
9 pies/4 friends =
9/4 = 2 1/4
D
2) 3x + 4y = 8
2x+y=42
a) (30, -19)
b) (31, -20)
c) (32,-22)
What is the answer
Answer:
C
Step-by-step explanation:
We can solve simultaneous equations using substitution method, elimination method or graphical method. But for this purpose, we will be using the elimination method.
3x+4y=8 Equation 1
2x+y=42 Equation 2
Multiply Equation 1 by 2 and equation 2 by 3, so as to get the same coefficient for x
2(3x+4y=8)= 6x+8y=16 Equation 3
3(2x+y=42)= 6x+3y=126 Equation 4
Subtract equation 4 from 3, to eliminate x
6x-6x=0
8y-3y= 5y
16-126= -110
We now have 5y=-110
Divide both sides by 5,
y= -110/5
= -22
Substituting for y in equation 2
2x+(-22)= 42
2x= 42+22
2x=64
x= 64/2
= 32
(x, y)
(32, -22)
Help ASAP I’ll give you brainliest
Answer:
-2/3
[tex]\sqrt50[/tex]
-1
-2.3145
Step-by-step explanation:
Answer:
-2/3
\sqrt50
-1
-2.3145
Step-by-step explanation:
please brainlist!
five more than the product of 14 and a number in algebraic expression
Answer:
14n+5
Step-by-step explanation:
Five more is +5
Product of 14 and a number would be 14n
So combined would be 14n+5
Stefan spent a third of his weekly allowance on clothes. To earn more money his parents let him wash the car for $5. Write and solve a two-step equation to determine his weekly allowance if he ended with $29. *Hint: start with: b/.... +....... =.......
Answer:
$36
Step-by-step explanation:
The amount spent on cloths is 1/3
The amount earned from washing the car is $5
Amount at the end of the week is $29
Let the amount earned that week be x
Then amount spent on cloths = 1/3x
so the equation is
x- 1/3 x+$5=$29
2/3 x=29-5
2/3 x= 24
x=(24*3)/2= $36
What is the volume of a cone with the height of 5.5 and a radius of 4
Answer:
29.33π cm³ or 92.10 cm³
Step-by-step explanation:
To find the volume of a cone with height 5.5 and radius 4, we will simply use the formula;
volume of a cone = [tex]\frac{1}{3}[/tex] π r² h
h = 5.5 and r= 4, we will simply plug in these values into our formula
volume of a cone = [tex]\frac{1}{3}[/tex] × π × (4)² (5.5)
= [tex]\frac{1}{3}[/tex] ×π × 16 × 5.5
=88π / 3
=29.33π
volume of cone = 29.33π
But π= 3.14
plugging in π=3.14, we have;
volume of cone = 29.33(3.14)=29.10
Answer:
88/3
Step-by-step explanation:
i just did the assignment
PLS HELP
What is the volume of the right rectangular prism shown?
A. 8 un3
B. 20 un3
C. 24 un3
D. 12 un3
The volume of the given rectangular prism is option C. [tex]24 un^{3}[/tex].
Step-by-step explanation:
Step 1:
The dimensions of the given rectangular prism are 4 units × 3 units × 2 units.
So we take the length equals 4 units, the width is equal to 3 units and the height is 2 units.
Step 2:
The volume of this rectangular prism is calculated by multiplying the given prism's length, its width, and its height.
The Volume of the given rectangular prism = [tex]( Length) (Width) (Height) = (4units) (3units) (2 units) = 24 unit^{3} .[/tex]
So the given right rectangular prism's volume is [tex]24 unit^{3}[/tex] which is option C.
HELP WILL GIVE BRANLIEST! WILL RATE! AND SAY THANKS!!!
A spherical ball of wax with a radius of 8 inches is melted and poured into a container shaped like a rectangular prism with a 14 inch x 16 inch base. What is the height of the melted wax in the new shape?
Answer:
9.57 inch
Step-by-step explanation:
(4/3)×pi×8³ = 14×16×h
h = (4/3)×pi×8³ ÷ (14×16)
h = 64pi/21 inch
Or, 9.57 inch (3 sf)
Look at the diagram. If RS = 15 and RT = 18, then ST = _.
33
Answer:
RS = 15 and RT = 18, then ST = 3! :D
Step-by-step explanation:r = 1 --> s=15 & t=18 so st = 270
r = 3 --> s = 5 & t = 6 so st = 30
r = 5 --> s = 3 & t = 3.6 so st = 10.8
etc
==============
In literal terms:
s = 15/r
t = 18/r
Step-by-step explanation:
marco wants to buy 2 books that cost 20$ each. He can save $5 a week. Draw diagrams and write equations to find how many weeks it will take hime to save enough money to buy the books.
Answer:
8 weeks
Step-by-step explanation:
because you multiply the two books to get the total price then divide by 5 to get how many weeks he has to save 5 dollars
Help please with answer
Answer:
None of the above
Step-by-step explanation:
The common ratio 10 means we are starting with 4.5 and multiplying that by 10 each time:
4.5*10=45
45*10=450
450*10=4500
As you can see, this does not match any of the answers
Let f be the function given by f(x)=3xsinx. What is the average value of f on the closed interval 1≤x≤7 ?
The average value of f(x) = 3x sin(x) on the interval [tex]\( 1 \leq x \leq 7 \) is approximately \( -1.6204 \).[/tex]
To find the average value of a function f(x) on a closed interval [a, b], we use the formula:
[tex]\[ \text{Average value} = \frac{1}{b - a} \int_{a}^{b} f(x) \, dx \]In this case, the function \( f(x) = 3x \sin(x) \) and the closed interval is \( 1 \leq x \leq 7 \).So, the average value of \( f(x) \) on the interval \( 1 \leq x \leq 7 \) is:\[ \text{Average value} = \frac{1}{7 - 1} \int_{1}^{7} 3x \sin(x) \, dx \][/tex]
[tex]\[ \text{Average value} = \frac{1}{6} \int_{1}^{7} 3x \sin(x) \, dx \][/tex]
Now, we need to compute the integral. We can do this using integration by parts:
[tex]Let \( u = 3x \) and \( dv = \sin(x) \, dx \).Then, \( du = 3 \, dx \) and \( v = -\cos(x) \).Using the integration by parts formula:\[ \int u \, dv = uv - \int v \, du \]\[ \int_{1}^{7} 3x \sin(x) \, dx = \left[ -3x \cos(x) \right]_{1}^{7} - \int_{1}^{7} (-\cos(x)) \cdot 3 \, dx \][/tex]
[tex]\[ = \left[ -3x \cos(x) \right]_{1}^{7} + 3 \int_{1}^{7} \cos(x) \, dx \]\[ = \left[ -3x \cos(x) \right]_{1}^{7} + 3 \left[ \sin(x) \right]_{1}^{7} \]\[ = \left[ -21 \cos(7) + 3 \sin(7) \right] - \left[ -3 \cos(1) + 3 \sin(1) \right] \][/tex]
Now, let's compute these values:
[tex]\[ \text{Average value} = \frac{1}{6} \left[ \left( -21 \cos(7) + 3 \sin(7) \right) - \left( -3 \cos(1) + 3 \sin(1) \right) \right] \]\[ \text{Average value} = \frac{1}{6} \left[ (-21 \times 0.7539 + 3 \times 0.6560) - (-3 \times 0.5403 + 3 \times 0.8415) \right] \]\[ \text{Average value} = \frac{1}{6} \left[ (-15.8359 + 1.9680) - (-1.6209 + 2.5245) \right] \][/tex]
[tex]\[ \text{Average value} = \frac{1}{6} \left[ -13.8679 + 4.1454 \right] \]\[ \text{Average value} = \frac{1}{6} \times (-9.7225) \]\[ \text{Average value} \approx -1.6204 \][/tex]
So, the average value of f(x) = 3x sin(x) on the interval [tex]\( 1 \leq x \leq 7 \) is approximately \( -1.6204 \).[/tex]
The average value of [tex]\(f(x) = 3x \sin(x)\)[/tex] on the interval [tex]\(1 \leq x \leq 7\)[/tex] is approximately 1.879.
To find the average value of [tex]\( f(x) = 3x \sin(x) \)[/tex]on the closed interval [tex]\( 1 \leq x \leq 7 \)[/tex], we can use the formula for the average value of a function on a closed interval [a, b] :
[tex]\[ \text{Average value} = \frac{1}{b - a} \int_a^b f(x) \, dx \][/tex]
In this case, a = 1 and b = 7, so:
[tex]\[ \text{Average value} = \frac{1}{7 - 1} \int_1^7 3x \sin(x) \, dx \][/tex]
Now, we need to evaluate the integral:
[tex]\[ \int_1^7 3x \sin(x) \, dx \][/tex]
This integral can be evaluated using integration by parts or by using a software tool. After evaluation, we find that the average value is approximately 1.879.
So, the correct answer is 1.879.
Complete Question:
Let f be the function given by f(x)=3xsinx. What is the average value of f on the closed interval 1≤x≤7 ?
−14.764
−2.461
1.879
8.161
can u help me plz and thank u
Answer:
hey
Step-by-step explanation:
angle 7x-9 +angle 4x=90°
11x=90+9
11x=99
x= 9°
Answer:
∠CBD = 54°
Step-by-step explanation:
∠ABC = 90°
∠ABD + ∠CBD = ∠ABC
4X + 7X -9 = 90
11X = 90+9
11X = 99
X = 99/11
X=9°
∠CBD = (7X -9)° = 7 * 9 - 9 = 63-9 = 54°
Write and evaluate the expression. Then, check all that apply.
The difference of a number and ninety;
When a = 102
Answer:
C,D,E,H 2020 edge
Step-by-step explanation:
I did the assignment
Answer:C D E H
Step-by-step explanation:
47%
a) The ratio 20 minutes to 1 hour can be written in the form 1: n.
Find the value of n. n =
Answer:
1hr=60minutes
ATQ,20 minutes/60 minutes=1/n
1/3=1/n
so the value of n is 3...
Step-by-step explanation: Hope i helped please give brainliest!
Solve this system by elimination: 3x + 2y = 18 5x – 2y = 14
Answer:
(4,3)
Step-by-step explanation:
3x + 2y = 18
5x – 2y = 14
Add the two equations together to eliminate y
3x + 2y = 18
5x – 2y = 14
------------------------
8x = 32
Divide each side by 8
8x/8 = 32/8
x = 4
Now determine the value for y
3(4) +2y = 18
12 +2y =18
Subtract 12 from each side
12-12+2y = 18-12
2y = 6
Divide by 2
2y/2 =6/2
y=3
Answer:
x=4 and y=3
Step-by-step explanation:
x+2y=18
5x−2y=14
Add these equations to eliminate y:
8x=32
Then solve8x=32for x:
8x=32
8x
8
=
32
8
(Divide both sides by 8)
x=4
Now that we've found x let's plug it back in to solve for y.
Write down an original equation:
3x+2y=18
Substitute4forxin3x+2y=18:
(3)(4)+2y=18
2y+12=18(Simplify both sides of the equation)
2y+12+−12=18+−12(Add -12 to both sides)
2y=6
2y
2
=
6
2
(Divide both sides by 2)
y=3
Answer:
x=4 and y=3
A rectangular poster has an area of 38 square feet. It is 9 1/2 feet wide at its base. What is the height of the poster?
By using the formula (Area = Length x Width) we can rearrange the equation to find the height of the rectangular poster. It comes out to be 4 feet.
Explanation:To answer your question, we must use the formula for the area of a rectangle, which is Area = Length x Width. Here, the area of the poster is given as 38 square feet and the width is 9.5 feet. The length is what we're trying to find. We can set this up as an equation 38 = Length x 9.5. To find the Length, we divide both sides of the equation by 9.5 resulting in Length = 38 ÷ 9.5. Solving the equation gives us a length of approximately 4 feet. So, the 'height' of the poster would be 4 feet.
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