The passenger car and the freight car travel towards each other from places A and B at the same time. After 3 hours, the passenger car arrives at the midpoint. The truck is 42 kilometers away from the midpoint. It is known that the speed of the truck is (5/7) that of the passenger car. How many kilometers are there between A and B?
客车和货车同时从甲乙两地同时相向而行，3小时后，客车到达中点．货车离中点还有42千米，已知货车的速度是客车的(5/7)，甲乙两地相距多少千米？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">42 / 3 / (2/7)</gadget>
<output>49</output>

<gadget id="calculator">49 * 3 * 2</gadget>
<output>294</output>

<result>294</result>