A fruit shop stipulates that if the purchased litchi does not exceed 10 kilograms, the price per kilogram will be 3 yuan; if it exceeds 10 kilograms, the excess price will be reduced by 10% per kilogram. How many kilograms of fruit someone buys, the money he pays is 59.7 yuan.
某水果店规定，如果购买荔枝不超过10千克，则每千克售价3元；如果超过10千克，则超过部分每千克降价10%．某人购买水果多少千克，他应付的钱为59.7元．
<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">59.7 - 30</gadget>
<output>29.7</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">3 * (9/10)</gadget>
<output>27/10 = around 2.7</output>

<gadget id="calculator">29.7 / (27/10)</gadget>
<output>11</output>

<gadget id="calculator">10 + 11</gadget>
<output>21</output>

<result>21</result>