The product of 4.6 times 2.5 plus 3.7 times a number, the sum is 30, find this number?
4.6乘2.5的积加上一个数的3.7倍，和是30，求这个数？
<gadget id="calculator">4.6 * 2.5</gadget>
<output>11.5</output>

<gadget id="calculator">30 - 11.5</gadget>
<output>18.5</output>

<gadget id="calculator">18.5 / 3.7</gadget>
<output>5</output>

<result>5</result>