Two cars, A and B, start from the same place at the same time. After 2.4 hours, the distance between them is 216 kilometers. The speed of car A is 42 km/h. Find the speed of car B?
甲、乙两辆汽车同时从同一地点出发，相背而行2.4小时后相距216千米，甲车的速度是42千米/时，求乙车的速度？
<gadget id="calculator">216 / 2.4</gadget>
<output>90</output>

<gadget id="calculator">90 - 42</gadget>
<output>48</output>

<result>48</result>