A. you plug in to a calculator, which will give 1840.986 so you need to round up to 1840.99. if you truncate it to .98 then he won't reach 2000 in 3 years
b. for this one if you look at the equation given to find the principle it is principle = result (1+rate) ^ -time
if you re arrange this you get result=principle (1+rate)^time so result = 1840.99(1.028)^5 = 2113.57
I can tell by the first 3 or so numbers that the sequence is decreasing by 6 each time, so when you go from 61- blank - 49 it has to be 55 and same with the other one.