The distance between A and B is 390 kilometers. Two cars A and B drive from A and B respectively at the same time. After 3 hours, the two cars meet. It is known that car A travels 60 kilometers per hour, how many kilometers per hour does car B travel? (column equation solution)
甲乙两地相距390千米，A、B两车分别从甲乙两地同时相向开出，经过3小时两车相遇．已知A车每时行驶60千米，B车每时行驶多少千米？(列方程解答)
<gadget id="calculator">60 * 3</gadget>
<output>180</output>

<gadget id="calculator">390 - 180</gadget>
<output>210</output>

<gadget id="calculator">210 / 3</gadget>
<output>70</output>

<result>70</result>