Xiaohua went to climb a mountain. He went up the mountain at 2.8 kilometers per hour, reached the top of the mountain in 3.5 hours, and then returned by the same road, at a speed 1.25 times that of going up the mountain. How long did it take Xiaohua to go down the mountain?
小花去爬山，他上山每小时行2.8千米，3.5小时到达山顶，再按原路返回，速度是上山时的1.25倍．小华下山用了多少时间？
<gadget id="calculator">2.8 * 1.25</gadget>
<output>3.5</output>

<gadget id="calculator">3.5 / 3.5</gadget>
<output>1</output>

<gadget id="calculator">2.8 * 1</gadget>
<output>2.8</output>

<result>2.8</result>