Two people, A and B, set off from A and B at the same time and walk towards each other. The speed ratio of A and B is 4:3. After they meet, they continue to move forward. A arrives at B and B arrives at A immediately. Go back along the original road, and it is known that the place where the two met for the second time is 30 kilometers away from the place where they met for the first time, how many kilometers is the distance between A and B?
甲、乙二人分别从A、B两地同时出发，相向而行，甲、乙的速度之比是4：3，二人相遇后继续行进，甲到达B地和乙到达A地后都立即沿原路返回，已知二人第二次相遇的地点距第一次相遇的地点30千米，则A、B两地相距多少千米？
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

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

<gadget id="calculator">(4/7) * 3</gadget>
<output>12/7 = around 1.714286</output>

<gadget id="calculator">2 - (12/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(4/7) - (2/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">30 / (2/7)</gadget>
<output>105</output>

<result>105</result>