A person receives a salary of 240 yuan, there are 2 yuan, 5 yuan, and 10 yuan, a total of 50 pieces of RMB, and the number of 2 yuan and 5 yuan pieces is the same, so how many pieces of 10 yuan are there?
某人领得工资240元，有2元，5元，10元三种人民币共50张，其中2元和5元的张数一样多，那么10元的有多少张．
<gadget id="calculator">260 / 13</gadget>
<output>20</output>

<gadget id="calculator">2 * 20</gadget>
<output>40</output>

<gadget id="calculator">50 - 40</gadget>
<output>10</output>

<result>10</result>