10 children play 3 sets of chess. They play from 1:00 pm to 5:00 pm. How many hours does each person play on average?
10个小朋友玩3副象棋，他们从下午1：00玩到5：00，平均每人玩了多少小时．
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 * 3 * (1/5)</gadget>
<output>12/5 = around 2.4</output>

<result>12/5 = around 2.4</result>