Xiaoming's bedroom area is 12 square meters, and it costs 720 yuan to lay the floor for this room. The bedroom area of his father and mother is 15 square meters. How much does it cost to lay the same floor? (Solve with ratio)
小明的卧室面积是12平方米，给这个房间铺地板用去720元，他爸爸、妈妈的卧室面积是15平方米，铺同样的地板，要用多少元？(用比例解)
<gadget id="calculator">720 / 12</gadget>
<output>60</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">60 / (1/15)</gadget>
<output>900</output>

<result>900</result>