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355The current of a stream runs at 4 km an hour. A boat goes 6 km and backto the starting point in 2 hours. The speed of the boat in still water s(a) 6 km/hr |
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Answer» Let the speed in still water be x km/hrThen, 6/x + 4 + 6/x - 4 = 2⇒ 6[ x - 4 + x + 4] = 2(x2- 16)⇒ x2- 6x - 16 = 0⇒ (x - 8) (x + 2) = 0∴ x = 8 km/hr |
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