Question dd0a0

Feb 25, 2017

$\frac{1}{8}$

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 $\frac{72000}{24000} =$ 3 half-lives in this time.

Thus, a half of a half of a half = $\frac{1}{2} \cdot \frac{1}{2} \cdot \frac{1}{2}$ = $\frac{1}{8}$ the original amount.

equation method

"Final Amount" = "Initial Amount" * (0.5)^("Time"/"Half Life")

$\text{Final Amount" = "Initial Amount} \cdot {\left(0.5\right)}^{3}$

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

And so the fraction is $\frac{1}{8}$