Question
A boat covers 180 km each in upstream and downstream in
a total time of 10 hours. It also takes 5 hours to travel 40 km upstream and 140 km downstream. How far will the boat travel in still water in 6 hours 20 minutes?Solution
ATQ,
Let speed of boat in upstream and downstream be ‘x’ km/h and ‘y’ km/h, respectively. So, 180/x + 180/y = 10…………..(1) And, 40/x + 140/y = 5……………….(2) Solving equation (1) and (2), we get x = 36 and y = 48 Speed of boat in still water = (36 + 48)/2 = 42 km/h 6 hour 20 minutes = 6 + 20/60 = 19/3 hours Desired distance = (19/3) × 42 = 266 km
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