Answer:
It seems that problem might have an error.
population = 600 * e ^ (.02*t) where e = 2.718281828459
So, at day 1 we have
day 1 population = 600 * 2.718281828459 ^(.02*1) = 32.62
day 2 population = 600 * 2.718281828459 ^(.02*2) = 88.67
We can see that the population doubles in less than one day but the lowest of those multiple choices is 34.657 days
Explanation: