A walks up the stairs twice as fast as B, and there is an upward escalator (escalator) running from the first floor to the second floor. Two people walk upstairs from the escalator. As a result, A walks 10 steps to reach the upstairs, and B walks 6 steps to reach the upstairs. How many steps does this escalator have?
甲步行上楼梯的速度是乙的2倍，一层到二层有一上行滚梯(自动扶梯)正在运行．二人从滚梯步行上楼，结果甲步行了10级到达楼上，乙步行了6级到达楼上．这个滚梯共有多少级？
<gadget id="calculator">6 / 1</gadget>
<output>6</output>

<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">6 / 1 / 5</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) - 1</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / (1/5)</gadget>
<output>20</output>

<result>20</result>