Two people, A and B, start from A and B at the same time, and run back and forth between A and B. A runs 3 meters per second, and B runs 7 meters per second. If the distance between their third encounter and the fourth encounter point is 150 meters, then how many meters is the distance between A and B?
甲乙二人分别从A、B两地同时出发，在A、B两地两地之间往返跑步，甲每秒跑3米，乙每秒跑7米．若果他们第三次相遇与第四次相遇点的距离是150米，那么A、B之间的距离为多少米．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">5 * (3/10)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) - 1</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">7 * (3/10)</gadget>
<output>21/10 = around 2.1</output>

<gadget id="calculator">(21/10) - 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/2) - (1/10)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">150 / (2/5)</gadget>
<output>375</output>

<result>375</result>