When A and B are multiplied together, if A increases by 8.5 and B remains the same, the product increases by 19.55; if B increases by 8.5, A remains the same, and the product increases by 39.1. What is the product of number A times number B?
甲乙两数相乘，如果甲数增加8.5，乙数不变，积增加19.55；如果乙数增加8.5，甲数不变，积增加39.1．甲数乘乙数的积是多少？
<gadget id="calculator">19.55 / 8.5</gadget>
<output>2.3</output>

<gadget id="calculator">39.1 / 8.5</gadget>
<output>4.6</output>

<gadget id="calculator">2.3 * 4.6</gadget>
<output>10.58</output>

<result>10.58</result>