If a pile of coal burns 15 kg per day on average, it can burn for 120 days. How many days can you burn if you burn 3 kilograms less per day on average?
一堆煤如果平均每天烧15千克，可以烧120天．如果平均每天少烧3千克，可以烧多少天？
<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<gadget id="calculator">15 * 10</gadget>
<output>150</output>

<result>150</result>