...........Gloria deposited $500 into a bank account that earned 7.5% simple interest each year. She earned $225 in interest before closing the account. If no money was deposited into or withdrawn from the account, for how many years was the money in the account? Round your answer to the nearest whole year.
1st year... 500 = 100% 5 = 1% 2.5 = 1/2% or .5% So, you have to do 5 x 7 to get 35 which is 7% then you have to tack on the 2.5 to get 7.5%
2nd year... 537.5 = 100% 5.375 = 1% 2.6875 = 1/2% or .5% So now 5.375 x 7 = 37. 625 + 2.6875 (I will round at the end) = 40.3125 So 37.5 + 40.31 (rounding!) = 77.81 in interest so far.
3rd year... 537.5 + 40.31 = 577.81 = 100% 5.77 = 1% 2.89 (was 2.885 but round up) = 1/2% or .5% so 5.77 x 7 = 40.39 + 2.89 = 43. 28 = 7.5% 577.81 + 43.28 = 621.09
