Xiao Ming wants to go to the 15th floor of a building. It took him 100 seconds to walk from the first floor to the fifth floor. If he walks to the 15th floor at the same speed, how many seconds will it take?
小明要到一栋楼的第15层上去，他从第一层走到第五层用了100秒，如果用同样的速度走到15层，还要多少秒．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">15 - 1</gadget>
<output>14</output>

<gadget id="calculator">25 * 14</gadget>
<output>350</output>

<gadget id="calculator">350 - 100</gadget>
<output>250</output>

<result>250</result>