Boomtown urban planners expect the city’s population to increase by 10% per year over the next two years. If that projection were to come true, the population two years from now would be exactly double the population of one year ago. Which of the following is closest to the percent population increase in Boomtown over the last year?
let X be the population now. So 2yrs it will be 1.21x
Lets say X=100
so 2yrs from now 1.21(100)--> 121
Now 1 yr ago from when the population was 100 it was 121/2 = 60.5 or ~60
1 yr later (Now) its 100. So 100-60/60 = a bit less than 2/3 (b/c of 60.5).
So D is the closest and therefore the answer.