Question
Find the time taken by boat D to cover downstream
distance, if the total time taken to complete the journey is 12.5 hours?Solution
Speed of boat D in still water = 6 km/hr Speed of stream = 2 km/hr Total time taken by boat D for entire journey = 12.5 hours Let, total distance travelled by boat D = d kms Upstream distance = 66% of d = kms Downstream distance = kms  Upstream speed = 4 km/hr Downstream speed = 8 km/hr Total time taken by boat D = Time taken for upstream + time taken for downstream + = 12.5 On solving the above equation, we get, d = 60 kms Downstream distance = = 20 kms Time taken = = 2.5 hours
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