The distance between the two places is 300 kilometers long. Two cars drive in opposite directions from the two places at the same time. After 2.5 hours, the distance between the two cars is still 50 kilometers. It is known that one car travels 45 kilometers per hour, how many kilometers per hour does the other car travel? (solution by equation)
两地之间路程长300千米，两辆汽车同时从两地相向开出，2.5小时后两车还相距50千米．已知一辆汽车每小时行45千米，另一辆汽车每小时行多少千米？(用方程解)
<gadget id="calculator">45 * 2.5</gadget>
<output>112.5</output>

<gadget id="calculator">300 - 112.5 - 50</gadget>
<output>137.5</output>

<gadget id="calculator">137.5 / 2.5</gadget>
<output>55</output>

<result>55</result>