# Question #dd0a0

##### 1 Answer

Feb 25, 2017

#### Explanation:

You can logic it out, or use the equation.

**logic method**

A half life is the time it takes for there to be half the amount. The total time is 72000 and the half life is 24000,

then there have been **3 half-lives in this time**.

Thus, a half of a half of a half =

**equation method**

#"Final Amount" = 1/8"Initial Amount"

And so the fraction is