Question #22231

A man drove 220km in 3.5 hours. Part of the trip was at 60 km/h and the rest at 65 km/h. Find the time spent at a slower rate

Expert's answer

If part of the trip at 60 km/h was X hours

then the rest time is 3.5 - X

Total distance:

220 = 60*X + (3.5 - X)*65

220 -& 3.5*65 = 60*X - 65*X

5*X = 7.5

X = 1.5 h - part of the trip was at 60 km/h

3.5 - 1.5 = 2 h -part of the trip was at 65 km/h

then the rest time is 3.5 - X

Total distance:

220 = 60*X + (3.5 - X)*65

220 -& 3.5*65 = 60*X - 65*X

5*X = 7.5

X = 1.5 h - part of the trip was at 60 km/h

3.5 - 1.5 = 2 h -part of the trip was at 65 km/h

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