Question

A boat takes 1/12th time in moving a certain distance downstream than upstream. The ratio of the speed of the boat in still water and that of the current is

A 5:4 Correct Answer Incorrect Answer
B 9:7 Correct Answer Incorrect Answer
C 11:9 Correct Answer Incorrect Answer
D 13:11 Correct Answer Incorrect Answer
E None of these Correct Answer Incorrect Answer

Solution

Let the speed of boat in still water = x km/hr, and Speed of current = y km/hr Rate downstream = (x + y) km/hr, and Rate upstream = (x – y) km/hr Distance = Speed × Time ؞ (x - y) × 12t = (x + y) × t => 12x - 12y = x + y => 12x - x = 12y + y => 11x = 13y => x/y = 13/11 = 13 : 11

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