36. A student invested 3000 dollars of his student loan. Then received an interest of 400 dollars over 4 years.
Question: Find the interest rate per year.
=> 400 dollars is for 4 years of interest.
=> 400 / 4 = 100 dollars is the per year interest, now, let’s solve its percentage of interest rate.
=> 100 dollars / 3 000 dollars = 0.03
=> 0.03 * 100% = 3%
Thus, a student earned 3% annual interest rate for her 3000 dollars.
