Two cars drive from two places 450 kilometers apart at the same time, and after 4.5 hours meet, it is known that car B travels 55 kilometers per hour, how many kilometers per hour does car A travel? (Solution by the method of column equation)
两车同时从相距450千米的两地相对开出，经过4.5小时相遇，已知乙车每小时行55千米，甲车每小时行多少千米？(用列方程的方法解)
<gadget id="calculator">55 * 4.5</gadget>
<output>247.5</output>

<gadget id="calculator">450 - 247.5</gadget>
<output>202.5</output>

<gadget id="calculator">202.5 / 4.5</gadget>
<output>45</output>

<result>45</result>