There is a 10-story building. Due to a power outage, the elevator stops. It takes 30 seconds for someone to walk from the 1st floor to the 3rd floor. According to this calculation, how many seconds does it take for him to walk from the 3rd floor to the 10th floor.
有一幢10层的大楼，由于停电电梯停开，某人从1层走到3层需要30秒，照这样计算，他从3层走到10层需要多少秒．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<gadget id="calculator">15 * 7</gadget>
<output>105</output>

<result>105</result>