If a ball falls from a height, it bounces up to (2/5) the height of the fall. If the ball is dropped from a height of 30 meters, what is the height of the second bounce?
一个皮球从高处落下，它弹起的高度是下落高度的(2/5)．如果这个皮球从30米的高度落下，则第二次弹起的高度是多少米．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 * (2/5) * (2/5)</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>