The ratio of the number of people who subscribed to "Youth Monthly" in Class 61 and Class 62 is 3:4. It is known that Class 62 subscribed 24 copies. How many copies did Class 61 subscribe to?
六一班和六二班订《少年月刊》的人数比是3：4，已知六二班订了24份，六一班订了多少份？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">24 * (3/4)</gadget>
<output>18</output>

<result>18</result>