A batch of coal, if it burns 120 tons per day, can be burned in 20 days, if it burns 160 tons per day, how many days will it be burned? (Solve with ratio)
一批煤，如果每天烧120吨，20天可以烧完，如果每天烧160吨，几天烧完？(用比例解)
<gadget id="calculator">120 * 20</gadget>
<output>2_400</output>

<gadget id="calculator">2_400 / 160</gadget>
<output>15</output>

<result>15</result>