Two naughty children walk against the direction of the escalator, from one end of the escalator to the other end, the boy walked for 50 seconds, and the girl took 150 seconds. It is known that when the escalator is at rest, the boy walks 2 meters per second, and the girl walks every second. Walking 1 meter per second, how many meters is this escalator long?
两个顽皮的孩子逆着自动扶梯行驶的方向行走，从扶梯的一端到达另一端，男孩走了50秒，女孩用了150秒，已知扶梯在静止时，男孩每秒走2米，女孩每秒走1米，那么这个行动扶梯长多少米？
<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">1 / 150</gadget>
<output>1/150 = around 0.006667</output>

<gadget id="calculator">(1/50) - (1/150)</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">1 / (1/75)</gadget>
<output>75</output>

<result>75</result>