Question
Ratio of speed of a boat in still water to speed of stream
is 9:1 respectively.Ratio of the time taken by the boat to cover a distance of (x + 50) km upstream and (x – 70) km in downstream is 15:11 respectively. Find the value of x.Solution
ATQ,
Let speed of boat in still water and speed of stream is ‘9a’ km/h and ‘a’ km/h respectively.
Upstream speed = 9a – a = 8a km/h
Downstream speed = 9a + a = 10a km/h
So, [(x + 50)/8a]/[(x – 70)/10a] = 15/11
Or, 11(x + 50) = 12(x – 70)
Or, 11x + 550 = 12x – 840
Or, x = 1390
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