A and B set off from A and B at the same time and walk toward each other. After 1 hour and 20 minutes, A rides to the midpoint of A and B, and the distance from B is exactly 7.5 kilometers. It is known that A , B cycling speed ratio is 7:4. How many miles is the distance between A and B?
甲、乙两人同时从A、B两地同时出发，相向而行，1小时20分后，甲骑到A、B两地的中点，与乙的距离刚好是7.5千米，已知甲、乙骑车的速度比是7：4．A、B两地间的路程是多少千米？
<gadget id="calculator">7 / 4</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">(7/4) * 7.5</gadget>
<output>13.125</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(7/4) * (1/2)</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">(7/8) - (1/2)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">13.125 / (3/8)</gadget>
<output>35</output>

<result>35</result>