It takes Fang Fang 20 seconds to go from the first floor to the third floor. If she goes to the eighth floor at the same speed, how many seconds will it take?
方方从一楼到三楼要用20秒，如果她用同样的速度再到八楼，还需要多少秒．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">10 * 5</gadget>
<output>50</output>

<result>50</result>