This type of problem is known to be the rate of decay or
decomposition. In dealing with this type of problem, we would let Q to be the amount
present at any time, Qo as the initial amount, k as the rate constant and then
t as the number of hours to reduce the initial amount to the present amount. The
equation would be Q=Q0 times e^ -kt.
In letter a, the answer would be 98.7389 seconds. Meanwhile
in letter b the answer is 125.8548 seconds.
