The passenger car and the truck travel in opposite directions from the midpoint of A and B at the same time. After 3 hours, the bus arrives at A, and the truck is still 42km away from B. It is known that the speed ratio of trucks and passenger cars is 3:5. How many kilometers are there between A and B?
客车和货车同时从甲、乙两地的中点向相反方向行驶，3小时后，客车到达甲地，货车离乙地还有42km．已知货车和客车的速度比是3：5．甲、乙两地相距多少千米？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) * 14</gadget>
<output>42/5 = around 8.4</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(42/5) / (2/5)</gadget>
<output>21</output>

<gadget id="calculator">21 + 21 + 14</gadget>
<output>56</output>

<gadget id="calculator">56 * 3</gadget>
<output>168</output>

<gadget id="calculator">168 + 42</gadget>
<output>210</output>

<result>210</result>