When two numbers are multiplied, if the multiplicand increases by 2 and the multiplier remains unchanged, the product increases by 60; if the multiplicand remains unchanged and the multiplier increases by 5, the product increases by 65. So what is the original product.
两数相乘，若被乘数增加2，乘数不变，则积增加60；若被乘数不变，乘数增加5，则积增加65．那么原来的积是多少．
<gadget id="calculator">13 * 15</gadget>
<output>195</output>

<result>195</result>