The interest rate on a car loan has increased 50% over the last 10 years and is now 9%. What was the rate 10 years ago? (enter a percentage rounded to the nearest whole number)

lets suppose initial rate of interest we need to find = x

total rate of interest as 1.5x (50% + (consider 9% as) 100%) in decimal it will be 1.5

Total rate of interest = current rate of interest

1.5x=9%

initial rate of interest x = 9/1.5 = 6 Answer

to check you can calculate 50% of 6 which will be 3 and later verify