tour group goes to visit the Terracotta Army. The number of elderly people in the tour group is equivalent to (2/5) of middle-aged people, and the number of middle-aged people is equivalent to (5/3) of young people. It is known that there are 20 elderly people, and how many young people are there?
一个旅行团去参观兵马俑，旅行团内老年人的人数相当于中年人的(2/5)，中年人的人数相当于青年人的(5/3)．已知老年人有20人，青年人有多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">20 / (2/5) / (5/3)</gadget>
<output>30</output>

<result>30</result>