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# Boat A travels upstream from point X to point Y in 2 hours more than the time taken by Boat B to travel downstream from point Y to point Z. The distance between X and Y is 40 km and that distance between Y and Z is 24 km. The speed of Boat B in still water is 10 km/h and the speed of Boat A in still water is equal to the speed of Boat B downstream. What is the speed of Boat A in still water? (Consider the speed of the current to be the same).

 A) 20 km/h B) 10 km/h C) 12 km/h D) 14 km/h

 C) 12 km/h

Speed of current = x kmph

Rate downstream of boat B = (10 + x) kmph

Speed of boat A in still water = (10 + x)kmph

$$\Large \therefore$$ Rate upstream

= 10 kmph

According to the question,

$$\Large \frac{40}{10} - \frac{24}{10 + x} = 2$$

=> $$\Large \frac{24}{10 + x} = 4 - 2 = 2$$

=> 10 + x = 12

=> x = 2 kmph

$$\Large \therefore$$ Speed of boat A in still water

= 10 + 2 = 12 kmph

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