Arun, Barun and Kiranmala start from the same place and travel in the same direction at speeds of 30 km/hr, 40 km/hr and 60 km/hr respectively. Barun starts two hours after Arun. If Barun and Kiranmala overtake Arun at the same instant, how many hours after Arun did Kiranmala start?
Explanation:
Arun has travelled 60 km when Barun starts.
Barun overtakes Arun in 60/(40 – 30) = 6 hrs
In this time, Barun travels 6 × 40 = 240 km from the starting point.
Kiranmala overtakes Arun at the same point.
Kiranmala takes 240/60 = 4 hrs to reach there.
Arun takes 240/30 = 8 hrs to reach there.
∴ Kiranmala starts 8 – 4 = 4 hrs after Arun.
Hence, option (c).
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