pile of coal can be burned for 18 days by burning 15 tons of coal per day on average. If it burns 12 tons of coal per day on average, how many days can it be burned?
一堆煤平均每天烧15吨可以烧18天，如果平均每天烧12吨，可以烧多少天？
<gadget id="calculator">18 / 12</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">15 * (3/2)</gadget>
<output>45/2 = around 22.5</output>

<result>45/2 = around 22.5</result>