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WAEC Mathematics 2002 Question 43

Question 43

Ratio, Percentages and Rates

To arrive on schedule, a train is to cover a distance of 60km at 72km/hr. If it starts 10 minutes late, at what speed must it move to arrive on schedule?

  1. A.60km/hr
  2. B.80 km/hr
  3. C.90km/hr
  4. D.108km/hr
Show the answer and explanation

Answer: C (90km/hr)

Explanation

Scheduled time = 60/72 h = 50 min. Starting 10 min late leaves 40 min = 2/3 h, so speed = 60 ÷ 2/3 = 90 km/h.