Multiple choice

The sum of the speeds of boat 'A' and boat 'B', in stillwater is 12 km/hr. The speed of stream is 5 km/hr. If boat'A' takes 24 hours to cover 264 km in downstream, then findthe time taken by boat 'B' to cover 176 km in downstream.

  1. 16 hours

  2. 12 hours

  3. 18 hours

  4. 22 hours

  5. 11 hours
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A Correct answer
Explanation

Boat A downstream speed = 264 / 24 = 11 km/hr. Downstream speed = Boat speed + Stream speed. 11 = V_A + 5, so V_A = 6 km/hr. Since V_A + V_B = 12, V_B = 6 km/hr. Boat B downstream speed = 6 + 5 = 11 km/hr. Time = 176 / 11 = 16 hours.

AI explanation

Using the downstream speed formula, boat A's speed in downstream is 264 divided by 24, which is 11 km per hour. Since the stream speed is 5 km per hour, boat A's speed in still water is 11 minus 5, or 6 km per hour. Given the sum of their speeds in still water is 12 km per hour, boat B's speed in still water is 12 minus 6, equaling 6 km per hour. Boat B's downstream speed is 6 plus 5, which is 11 km per hour, and the time to cover 176 km is 176 divided by 11, equaling 16 hours.

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