Here we go, just my 50 cent:
1. This one is insufficient because it says that quantity of bacteria increased each year by the same percent each year from 1922 to 1937. So it means for 15 years (or should I say 1937-1922+1=16 years, if it said including) the quantity increased by the same percent. If the same percent was 100% then we get one answer but it could be also 0.3% each year, hence 1 is out not sufficient.
2. This is more trickier, since it says by at most 1 percent each year. So we will get something similar to compound interest, i.e. Q*(1+p/100)^t=Q*1.15 or in our case Q*(1+0.01)^t>=Q*1.15 OR 1.01^t>=1.15. So we get something way out of 2-min GMAT problem, so where we have to find such t so 1.01 to the power of t would be >=1.15, It was onerous to find the values for t by regular calculation, so I used MS Excel
and go the following, as we see if t=15, then the 1.01^15>=1.15 or 1.01^15>1.15. However, the question stem 2 says that at most 1
it could as easily interpreted not 1 percent but 0.9 percent and we would get totally different result, thus 2 is out.
Combining 1 and 2 we get that quantity of bacteria each year increased by at most 1 percent - we get one answer, but also it could be by 0.7 percent each year and we get different answer. The musings about leave us with answer (E) we need more precise details to expound upon this problem or just information provided is insufficient.
Please, correct me if I went awry
God loves the steadfast.