Cars A and B are traveling towards each other from places A and B at the same time, and meet each other in 4 hours. The speed of car A is 15 kilometers faster than that of car B per hour. It is known that the ratio of the speed of cars A and B is 5:4. What is the distance between A and B in miles?
甲、乙两车同时从A、B两地相向而行，4小时相遇，甲车的速度每小时比乙车快15千米，已知甲、乙两车的速度之比是5：4，则A、B两地相距多少千米．
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(5/9) - (4/9)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">60 / (1/9)</gadget>
<output>540</output>

<result>540</result>