Someone was going to the seventh floor of a building to do business, but unfortunately the elevator stopped. It took him 54 seconds to walk from the first floor to the fourth floor. How many seconds did it take to go up to the seventh floor at the same speed?
某人要到一栋大楼的第七层办事，不巧电梯停开．他从第一层走到第四层，用了54秒．若以同样的速度往上走到第七层，一共用了多少秒．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">54 / 3</gadget>
<output>18</output>

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

<gadget id="calculator">18 * 6</gadget>
<output>108</output>

<result>108</result>