Question 1159187
.
<pre>

Notice that  {{{140/2.1875}}} = 64 = {{{2^6}}}.


It means that 60 minutes comprise 6 half-life periods.



Thus one half-life period is   {{{60/6}}} = 10 minutes.


Therefore, the formula for G(t)  is  G(t) = {{{140*((1/2)^(t/10))}}},  where t is in minutes from the starting moment.


To answer the last question, substitute t= 53 into the formula


    G(53) = {{{140*0.5^5.3}}} = 3.553604 grams.
</pre>

-----------


Solved.  All the questions are answered.