Pierre invested $7500 in a savings account with a yearly interest rate of 3% for 14 years. How much simple interest did he earn?

Yearly interest return = 7500 x 3% = 7500 x 0.03 = 225

Since it's a simple interest then the amount of total interest will be

14 x 225 = $3150

(This is not asked by the problems. It's just indicatif: the total money will be 7500 + 3150 = $10,650)