Simple Interest = Money Amount + (Interest percentage of Money × number of years or months)
SI = 3500 + (3.5% of 3500 × 4)
SI = 3500 + (122.5 × 4)
SI = 3500 + 490
SI = 3990 !
He earned 3990 over 4 years. If you liked my answer, please make me the brainliest answer! :)