Question

An element with mass 640 grams decays by 7.3% per minute. How much of the element is remaining after 8 minutes, to the nearest 10th of a gram?

Answer 1

Solution

The exponential decay equation is given by :-

$y=A(1-r)^{t}$

 Where

A= Initial value ,

r = rate of decay in decimal and t is time.

As per given , we have

A= 640 gm

r= 7.3%=0.073

Then , our decay function will become :-

$y=640(1-0.073)^{t}$

$y=640(0.927)^{8}$

$y=640\times0.54530298264$

y=348.99

y=349.0

At t= 8 minutes, we have

Hence, after 8 minutes , the remaining amount of element = 349.0 gms.