Problema Solution

a courier travels to and from a manufacturing plant in 7 hours. his average speed to the plant is 80km/h, and the return trip averages 20km/h slower. how long did it take to reach the plant?

Answer provided by our tutors

let


t = the time of the travel to the plant


7 - t = the time of the travel from the plant


v1 = 80 km/h the average speed to the plant


v2 = 80 - 20 = 60 km/h the average speed of the return trip


since distance = speed*time we have:


v1t = v2(7 - t)


80t = 60(7 - t)


by solving we find:


t = 3 hr


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it takes 3 hours to reach the plant.