# Question #338a0

Jul 18, 2017

$6 125 g = 6.125 \cdot {10}^{- 3} k g$

#### Explanation:

Formula is ${m}_{l} = {m}_{s} \cdot {0.5}^{\frac{t}{h}}$, where:
${m}_{l}$ = mass left
${m}_{s}$ = starting mass
$t$ = time
$h$ = half life

Unit time for $h$ and $t$ must be the same.

So, we have ${m}_{l} = 98 \cdot {0.5}^{\frac{80}{20}}$, where $80$ and $20$ are the same unit of time.

$\frac{80}{20} = 4$

$98 \cdot {0.5}^{4} = 6.125 g$