A car travels from A to B at a speed of 80 km/h, arrives in 15 hours, and takes 12 hours to return. Find the speed when returning.
一辆汽车从甲地开往乙地，速度是80千米/时，15小时到达，返回时用了12小时，求返回时的速度．
<gadget id="calculator">15 / 12</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">80 * (5/4)</gadget>
<output>100</output>

<result>100</result>