If it takes 20 seconds to cut a rope into 5 sections, how many seconds will it take to cut it into 7 sections?
把一根绳子剪成5段要20秒，剪成7段要多少秒．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<result>30</result>