Question 1157954
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<pre>
The general formula is


    M = {{{M0*(1/2)^(t/98)}}},


where  M0  is the initial mass;  M is the current (remaining) mass, and "t" is time in days.



So, the answers (and the calculation work) are


    M = 100*((1/2)^(20/119.77)) = 89.07 grams.      <U>ANSWER</U>
</pre>

Solved.