In 2:5, if the former term is increased by 10, how much should the latter term be increased to keep the ratio constant.
在2：5中，如果前项增加10，要使比值不变，后项应增加多少．
<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">30 - 5</gadget>
<output>25</output>

<result>25</result>