It took 4 minutes for Uncle Wang to climb from the first floor to the fifth floor. At this speed, how many minutes would it take him to climb to the eighth floor? (There are no stairs on the first floor, and the number of stairs between each floor is equal)
王大爷从一楼爬到5楼用了4分钟，照这样的速度，他要爬到8楼共需要多少分钟．(一楼没楼梯，每层楼间的楼梯级数相等)
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">1 * 7</gadget>
<output>7</output>

<result>7</result>