Two cars A and B drive towards each other from two places 630 kilometers apart at the same time, and they meet on the way after 4 hours. It is known that car A travels 70 kilometers per hour, how many kilometers per hour does car B travel? (column equation solution)
甲乙两辆汽车从相距630千米的两地同时相向开出，4小时后在途中相遇，已知甲车每小时行70千米，求乙车每小时行多少千米？(列方程解答)
<gadget id="calculator">70 * 4</gadget>
<output>280</output>

<gadget id="calculator">630 - 280</gadget>
<output>350</output>

<gadget id="calculator">350 / 4</gadget>
<output>175/2 = around 87.5</output>

<result>175/2 = around 87.5</result>