Two vehicles, passenger and freight, travel opposite directions at the same time from the midpoint of A and B. After 3 hours, the bus arrives at B. At this time, the truck is still 42 kilometers away from A. It is known that the ratio of the speed of the truck to the bus is 5: 7. How many kilometers is the distance between A and B?
客货两车同时从甲、乙两地的中点向反而行，3小时后客车到达乙地，这时货车离甲地还有42千米，已知货车和客车的速度的比是5：7，求甲、乙两地路程是多少千米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(1/2) * (5/7)</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">(1/2) - (5/14)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">42 / (1/7)</gadget>
<output>294</output>

<result>294</result>