A is 5 times the number of B, if the number of A increases by 20, then the number of A is 7 times of the number of B, then what is the number of A?
甲是乙数的5倍，如果甲数增加20，则甲数是乙数的7倍，那么甲数是多少．
<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<result>50</result>