There are two piles of coal. The first pile is 4.5 tons, which consumes 0.36 tons per day, and the second pile of coal is 6 tons, which consumes 0.51 tons every day. After how many days, the remaining coal in the two piles will be equal?
有两堆煤，第一堆4.5吨，每天用去0.36吨，第二堆煤6吨，每天用去0.51吨，多少天后两堆剩下的煤相等？
<gadget id="calculator">6 - 4.5</gadget>
<output>1.5</output>

<gadget id="calculator">0.51 - 0.36</gadget>
<output>0.15</output>

<gadget id="calculator">1.5 / 0.15</gadget>
<output>10</output>

<result>10</result>