John invests in a bank and gets 10% simple interest. He invests $1000. How much money does he have after 3 years? Give me reasons, before answering the question
He gets 1000 * .1 = $100 a year. So after 3 years, he gets 100 * 3 = $300. So he has 300 + 1000 = $1300. So the final answer is 1300.