Someone goes to work on the tenth floor of a ten-story building. It takes him 80 seconds to walk from the first floor to the fifth floor. How many seconds will it take to continue to the tenth floor at the same speed?
某人到十层大楼的第十层办事，他从一层走到第五层用了80秒，那么以同样的速度继续走到第十层，还需要多少秒才能到达．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>