Question
The ratio of the speed of boat ‘A’ in still water,
the speed of boat ‘B’ in still water and the speed of the current is 7:4:2, respectively. If the time taken by boat ‘A’ to travel (7D – 20) km downstream is equal to the time taken by boat ‘B’ to travel (D + 65) km upstream, then find the value of ‘D’.Solution
Let, the speeds of boat ‘A’ and boat ‘B’, in still water and the speed of the current be 7x km/hr, 4x km/hr and 2x km/hr, respectively. According to the question, (7D – 20)/(7x + 2x) = (D + 65)/(4x – 2x) Or, 14D – 40 = 9D + 585 Or, 5D = 625 Or, D = 125
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