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2 years ago

PLEASE HELP ME!!!! I NEED TO TURN IN THIS IN 15 MINUTES

Mathematics

1 answer:

Musya8 [376]2 years ago

5 0

Answer: i cant see it

Step-by-step explanation:

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Use the exponential decay model, Upper A equals Upper A 0 e Superscript kt, to solve the following. The half-life of a certai

Akimi4 [234]

Answer:

It will take 7 years ( approx )

Step-by-step explanation:

Given equation that shows the amount of the substance after t years,

$A=A_0 e^{kt}$

Where,

$A_0$ = Initial amount of the substance,

If the half life of the substance is 19 years,

Then if t = 19, amount of the substance = $\frac{A_0}{2}$ ,

i.e.

$\frac{A_0}{2}=A_0 e^{19k}$

$\frac{1}{2} = e^{19k}$

$0.5 = e^{19k}$

Taking ln both sides,

$\ln(0.5) = \ln(e^{19k})$

$\ln(0.5) = 19k$

$\implies k = \frac{\ln(0.5)}{19}\approx -0.03648$

Now, if the substance to decay to 78% of its original amount,

Then $A=78\% \text{ of }A_0 =\frac{78A_0}{100}=0.78 A_0$

$0.78 A_0=A_0 e^{-0.03648t}$

$0.78 = e^{-0.03648t}$

Again taking ln both sides,

$\ln(0.78) = -0.03648t$

$-0.24846=-0.03648t$

$\implies t = \frac{0.24846}{0.03648}=6.81085\approx 7$

Hence, approximately the substance would be 78% of its initial value after 7 years.

5 0

3 years ago

4d + 7e = 68<br> -4d - 6e = -72<br> QUICK

Alexxx [7]

Step-by-step explanation:

by adding :

e=_4

d=24.....

6 0

2 years ago

<img src="https://tex.z-dn.net/?f=%5Cfrac%7Br%7D%7B2%7D%2B%5Cfrac%7Bs%7D%7Br%7D%20-%5Cfrac%7Br%7D%7B4%7D%2B%5Cfrac%7B1%7D%7B5%7D

zloy xaker [14]

Answer:

-1/20

Step-by-step explanation:

r/2 + s/r - r/4 + 1/5 =

= -1/2 + 0/(-1) - (-1)/4 + 1/5

= -1/2 + 1/4 + 1/5

= -10/20 + 5/20 + 4/20

= -5/20 + 4/20

= -1/20

3 0

3 years ago

2 - 7 ( 4x + 5 ) = -33 + 5x

Olegator [25]

2 - 28x - 35 = -33 + 5x
-33 - 28x = -33 + 5x
-33+33 = 5x+28x
0=33x
x=0

4 0

3 years ago

(18/10)(8/3) operación matemática

Anastaziya [24]

Answer:

4.8

Step-by-step explanation:

(18/10)(8/3)

18*8= 144

10*3= 30

144/30 =4.8

4 0

3 years ago