Liangliang's home is on the 15th floor of Block B in Huayuan District. Due to a power outage, Liangliang can only walk up the stairs. It took him 100 seconds to walk from the first floor to the fifth floor. If he uses the same speed, how many seconds will it take for Liangliang to return home?
亮亮家在花园小区B座第15层，由于停电，亮亮只能走楼梯．他从第1层走到第5层用了100秒，如果用同样的速度，亮亮回到家还需要多少秒．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<gadget id="calculator">15 - 5</gadget>
<output>10</output>

<gadget id="calculator">25 * 10</gadget>
<output>250</output>

<result>250</result>