# If the mass of a radioactive substance is 8 grams and it has half life of 4 hours, how much mass remains after 8 hours?

Nov 1, 2016

2 grams

#### Explanation:

The sample will lose half of its mass after 4 hours. The half life.

$\frac{8}{2} = 4$

The sample will lose half of the remaining four after another half life.

$\frac{4}{2} = 2$