Li Qiang bought 2-year treasury bonds with 500 yuan of New Year's money, with an annual interest rate of 2.8%. After the maturity, he donated the interest to the "Hope Project" to support poor and out-of-school children. How much can Li Qiang donate.
李强把500元压岁钱买了2年期国库券，年利率为2.8%，到期后他把利息捐给"希望工程"，支援贫困失学儿童，李强可以捐多少元．
<gadget id="calculator">2.8 / 100</gadget>
<output>0.028</output>

<gadget id="calculator">500 * 0.028 * 2</gadget>
<output>28</output>

<result>28</result>