Two cars drive from two places at the same time. The speed ratio of cars A and B is 3:4. When they meet, car B travels 50km longer than car A. Find the distance between the two places.
两辆车从两地同时开出，甲、乙两车的速度比是3：4，相遇时，乙车比甲车多行驶了50km，求两地之间的距离．
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(4/7) - (3/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">50 / (1/7)</gadget>
<output>350</output>

<result>350</result>