# The half-life of bromine-74 is 25 min. How much of a 6.0 mg sample is still active after 75 min?

##### 1 Answer

Jul 10, 2016

#### Answer:

#### Explanation:

Find the number of periods during which the disintegration of the radioiosotope took place.

During each period, half the original amount disintegrates.

Note that each arrow represents 1 period.