There are two piles of coal, A and B, and A pile of coal is 100 tons. If 10 tons of coal are transported from pile A to pile B, then pile A will be 5 tons less than pile B. Now after both piles have transported the same number of tons, the remaining pile of coal in pile B is 70% of pile A. At this time, how many tons of coal are left in Pile A?
有甲、乙两堆煤，甲堆煤100吨．如果把甲堆煤运往乙堆10吨，那么甲堆就比乙堆少5吨，现在两堆都运走相同的若干吨后，乙堆剩下的是甲堆剩下的70%．这时甲堆剩下的煤是多少吨？
<gadget id="calculator">100 - 10</gadget>
<output>90</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">100 * (7/10)</gadget>
<output>70</output>

<gadget id="calculator">5 - 10 - 70</gadget>
<output>-75</output>

<gadget id="calculator">90 + (-75)</gadget>
<output>15</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">15 / (3/10)</gadget>
<output>50</output>

<gadget id="calculator">100 - 50</gadget>
<output>50</output>

<result>50</result>