In one day the popuation grows by 13%. Let d be the number of days since there were 1100 bacteria and N(d) the number of bacteria on that day.
We are told that N(0) = 1100 and that N(d) = 1.13*N(d-1)
So N(1)=N(0)*1.13^1
N(2) = N(1)*1.13^1 = N(0)*1.13^2
N(3) = N(0)*1.13^3
If this trend continues N(29) = 1100*1.13^29
Rounding the answer you get 38,077.