21 trucks, each with a 2.5-ton payload, are needed to unload a freight train. how many trucks, each with a 3.5-ton payload, would be needed to do the same job? what is the constant of variation?

Tons needed to unload a freight train= 21×2.5 =52.5
number of 3.5-ton payload trucks needed to unload a freight train=52.5÷3.5 = 15

15 Trucks , Each With A 3.5-Ton Payloaf , Would be Needed To Do The Same Job. 

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