18000 dollars invested with 5% interest. => 18 000 dollars * 0.05 = 900 dollars for annual interest rate. Now, how much interest will he be earning in 3 years? => first year = 18 900 dollars * .05 = 945 dollars for the 2nd year => 2nd year = 18 900 dollars + 945 = 19 845 dollars 19845 * .05 = 992.25 => 3rd years = 19845 + 992.25 = 20837.25 total amount he will get back. For interest = 900 + 945 + 992.25 = $2837.25
