Mr. He deposited 3,000 yuan in the bank for a period of five years. When it expired, he got back a total of 3,621 yuan. Find the annual interest rate. (no tax on interest)
何老师把3000元钱存入银行，定期五年，到期时他共取回3621元，求年利率．(不缴利息税)
<gadget id="calculator">3_621 - 3_000</gadget>
<output>621</output>

<gadget id="calculator">621 / 5 / 3_000</gadget>
<output>207/5_000 = around 0.0414</output>

<result>207/5_000 = around 0.0414</result>