In 8:15, if the former term is multiplied by 2, to keep the ratio unchanged, what should be the latter term
在8：15中，如果前项乘2，要使比值不变，后项应多少
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<result>15</result>