Question

A train travels 68 km at an average speed of 51 km/h. It then travels another 20 km at an average speed of 40 km/h before reaching its destination. Calculate the average speed for the whole journey.

Also please give the solution of this problem.

Answer 1

time = distance / rate

travelling 68 km at 51 km/hour = 1 + (1/3) hours

travelling 20 km at 40 km/hour = .50 hours

total time = 1.8333333... hours

total distance = 68 + 20 = 88 kilometers

average speed = 88 km / 1.8333333... hours

average speed = 48 km / hour

Answer 2

`\boxed {\text {Time = Distance} / \text{Speed}}`

Given Distance = 68km Speed = 51 km/h:

Time = 68 ÷ 51 = 1 1/3 hour

Given Distance = 20km, Speed = 40 km/h:

Time = 20 ÷ 40 = 1/2 hour

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Find Total Distance:

Total Distance = 68 + 20 = 88km

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Find Total Time Taken:

Total Time = 1 1/3 + 1/2 = 1 5/6 hours

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Find Average Speed:

Speed = 88 ÷ 1 5/6 = 48 km/hour

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Answer: Average speed = 48 km/hour