The general equation use to calculate increasing or decreasing values
P(t) = A(1 + r)^t
where: P = New value A = original or starting amount r = rate (can be either increasing(+) or decreasing(-)) t = time period that increase/decrease take place.
So after 1 year at 3.8% interest P = 7500(1 + 0.038)^1 P = 7500(1.038) P = 7,785
Then after 1 year at 5.35 interest P = 7500(1 + 0.053)^1 P = 7500(1.054) P = 7,897.50