A and B climb a building with 16 floors. There are 20 steps between each two floors. They start at the same time. When A climbs to the 7th floor, B just climbs to the 5th floor. When climbing to the 16th floor, how many floors did B climb to?
甲、乙两人爬一幢16层的楼房，每两层之间有20阶台阶，两人同时开始，当甲爬到7楼时，乙正好爬到5楼，照这样的速度，当甲爬到16楼时，乙爬到了多少楼．
<gadget id="calculator">16 - 1</gadget>
<output>15</output>

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

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">6 / 4</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">1 / (3/2)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<result>11</result>