Asked by Elsy

If the sample has a half life of 5 seconds, how much is left after 25 seconds?

12.5%

25%

3.125%**

6.25%
Answered by Elsy
The other choice was

1.5625%
Answered by R_scott
25 s is 5 half-lives

(1/2)^5 = 1/32

looks correct