A matatu travels 120 km from Kisumu to Kericho at 40 km/h and returns along the same road at 60 km/h. What is its average speed for the whole journey?
Answer and explanation
Correct answer: C. 48 km/h
- Step 1: Time out = 120/40 = 3 h; time back = 120/60 = 2 h. Step 2. Total distance = 240 km and total time = 5 h. Step 3. Average speed = 240 / 5 = 48 km/h. Answer: 48 km/h. Why not the others: 50 km/h: That averages the two speeds, but more time is spent at the slower speed. 20 km/h: That is the difference of the speeds, not an average. 53 km/h: That is not the total distance divided by the total time.
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