Question

An element with a mass 310 grams decays by 5.7% per minute. How much of the element is remaining after 9 minutes, to the nearest 10th of a gram

Answer 1

Mass of an element = 310 grams

Percentage of the element that will decay in a minute = 5.7%

Quantity of the element that will decay in one minute :

`= (5.7 * 310)/(100)`

`= (1767)/(100)`

`= \tt17.67 \: grams`

Thus, 17.67 grams of the element will decay every minute.

Quantity of element that will decay after nine minutes :

`= 17.67 * 9`

`=\tt 159.03 \: grams`

Thus, 159.03 grams of the element will decay after 9 minutes.

Quantity of element that will remain after 9 minutes :

`= 310 - 159.03`

`= \tt150.97 \: grams`

Thus, 150.97 grams of the element will remain after nine minutes.

We can round off 150.97 to 151.00.

Therefore, 151.00 grams of the element will remain after 9 minutes.