Question

8.
The half-life of a certain radioactive material is 71 hours. An initial amount of the material has a mass of 722 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 17 hours. Round your answer to the nearest thousandth.

A)y=1/2(1/722)^1/71x; 0.103 kg
B)y=722(1/2)^1/71x; 611.589 kg
C)y=2(1/722)^1/71x; 0.414 kg
D)y=722(1/2)^71x; 0 kg

I think it's B, can someone explain this to me?

Answer 1

y=722(1/2)^1/71x
1/71x ???
I do not understand why this is so

Answer 2

amount = 722 (1/2)^(t/71) , where t is in hours

so after 17 hours ....

amount = 722(1/2)^(17/71)
= 722(.847076...)
= 611.589 -------------> choice B
= appr 612 kg

It would be more logical to use t as a variable for time instead of x, but hehh, whatever turns them on.

Answer 3

answers for the logarithmic quiz part 1
1.c
2.a
3.d
4.b
5.d
6.a
7.c
8.c
9.a

Answer 4

THX SO MUCH "satan"🖤

Answer 5

thanks satan