It takes a total of 30 seconds for Duoduo to go from the 1st floor to the 3rd floor. At this speed, how many seconds does it take her to go from the 1st floor to the 6th floor?
多多从1楼到3楼共需要30秒，照这样的速度，她从1楼到6楼共需要多少秒．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

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

<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">15 * 5</gadget>
<output>75</output>

<result>75</result>