A car travels from point A to point B through an uphill road of 240 kilometers and a downhill road of 160 kilometers. The speed of the car uphill is 40 kilometers per hour and the speed of downhill is 80 kilometers per hour. Ask this car How many hours does it take to return from point B to point A?
一辆车从甲地到乙地要经过240千米的上坡路，160千米的下坡路，汽车上坡的速度是每小时40千米，下坡的速度是每小时80千米，问这辆车从乙地返回甲地用多少小时？
<gadget id="calculator">160 / 40</gadget>
<output>4</output>

<gadget id="calculator">240 / 80</gadget>
<output>3</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<result>7</result>