Simplify this following question:

the half-life of strontium-90 is approximately 29 years. how much of a 500 g sample of strontium-90 will remain after 58 years

Yuliya22 [10]

Answer: 125 g

Step-by-step explanation:

$A = P_o\cdot e^{kt}\\\\\text{First, use the given information to find k:}\\\\\bullet A=\dfrac{1}{2}P_o\\\\\bullet k = unknown\\\\\bullet t=29\text{ years}\\\\\dfrac{1}{2}P_o=P_o\cdot e^{k(29)}\\\\\\\dfrac{1}{2}=e^{k(29)}\qquad divided\ both\ sides\ by\ P_o\\\\\\ln\bigg(\dfrac{1}{2}\bigg)=ln\bigg(e^{k(29)}\bigg)\qquad applied\ ln\ to\ both\ sides\\\\\\ln\bigg(\dfrac{1}{2}\bigg)=29k\qquad simplified-ln\ and\ e\ cancel\ out\\\\\\\dfrac{ln\bigg(\dfrac{1}{2}\bigg)}{29}=k\qquad divided\ 29\ from\ both\ sides\\\\\\-0.0239=k$

$\text{Now, use the following in the equation to solve for A:}\\\\\bullet A=unknown\\\bullet P_o=500\\\bullet k=-0.0239\\\bullet t=58\text{ years}\\\\A=500\cdot e^{(-0.0239)(58)}\\\\.\quad=500\cdot e^{-1.386}\\\\.\quad=125$

8 0

4 years ago

The vertices of triangle R'S'T' are R'(1, 3), S'(6, 4), and T'(4, 2). If triangle RST was dilated about the origin with a scale

sammy [17]

Answer:

R(1/3, 1), S(2, 4/3), T(4/3, 2/3)

Step-by-step explanation:

Dilation by a factor of 3 about the origin multiplies each coordinate by 3. To find what was multiplied by 3 to get the given coordinates, we divide the given coordinates by 3.

4 0

3 years ago

Read 2 more answers

Add 17 , 19 , 20 , 20 , and 23

worty [1.4K]

Answer:

99

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

erica is making necklaces and bracelets to se at the craft show. it takes her 3 hours to make a necklace and 2 hours to make a b

bagirrra123 [75]

Answer:

Erica should make at least 10 necklaces and 15 bracelets to maximize her profit of P = (18 x + 15 y)

Step-by-step explanation:

Let the number of necklaces made = x

Let the number of bracelets made by Erica = y

Now, the time taken to make each necklace = 3 hrs

⇒The time taken to make x necklaces = x times 3 hours = 3x

Also, the time taken to make each bracelet = 2 hrs

⇒The time taken to make y necklaces = y times 2 hours = 2y

So, total time taken to make x necklace and y bracelets = 3x + 2y

Now selling cost of 1 necklace = $18

Also, selling cost of 1 bracelet = $15

So, total selling price of x necklace and y bracelets = 18 x + 15 y

So according to the question:

x + y = 25 ..... (1)

3x + 2y = 60 .... (2)

Solving the above system substitute y = 25- x in (1)

we get: 3x + 2y = 60 ⇒ 3x + 2(25 -x) = 60

or, x = 10

⇒ y = 25 - x = 25 - 10 = 15, or y = 15

So, she should make at least 10 necklaces and 15 bracelets to maximize her profit of P = (18 x + 15 y)

8 0

3 years ago

Read 2 more answers

Write a two column proof. Given: 4y = 2x - 10; y = 6 Prove: x = 17

Ivenika [448]

4y=2x-10

Plug in y

4(6)=2x-10

Simplify

24=2x-10

+10 to both sides

24+10=2x-10+10

Simplify

34=2x

÷2 both sides

17=x

x=17

5 0

3 years ago