Qiangqiang donated 175 yuan at a time, which are 20 yuan and 5 yuan respectively. There are 23 tickets in total, how many of them are 5 yuan.
强强一次捐款175元，分别是20元和5元的，共有23张，其中5元的有多少张．
<gadget id="calculator">20 * 23</gadget>
<output>460</output>

<gadget id="calculator">460 - 175</gadget>
<output>285</output>

<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<gadget id="calculator">285 / 15</gadget>
<output>19</output>

<result>19</result>