The school bought a 150-meter-long plastic rope, cut off 7.5 meters first, and made 3 skipping ropes of the same length. According to this calculation, how many skipping ropes can be made from the remaining plastic ropes? (answer with ratio)
学校买来150米长的塑料绳，先剪下7.5米，做3根同样长的跳绳．照这样计算，剩下的塑料绳还可以做多少根跳绳？(用比例解答)
<gadget id="calculator">150 - 7.5</gadget>
<output>142.5</output>

<gadget id="calculator">7.5 / 3</gadget>
<output>2.5</output>

<gadget id="calculator">142.5 / 2.5</gadget>
<output>57</output>

<result>57</result>