Explanation:

- The problem gives us two scenarios. The downstream and upstream distances are covered at different speeds because of the stream.

- The speed of the boat in still water is 12 km/h, which is three times the speed of the stream. So, the speed of the stream is 4 km/h.

- Downstream speed = speed of the boat + speed of the stream = 12 + 4 = 16 km/h.

- Upstream speed = speed of the boat - speed of the stream = 12 - 4 = 8 km/h.

- From the information given:

- Downstream: (X + 60) km in 5 hours at 16 km/h.

- Upstream: (Y + 32) km in 8 hours at 8 km/h.

- We need to find the time taken to travel (X + 3Y/8) km downstream.

- Downstream speed = 16 km/h, so time = Distance / Speed = (X + 3Y/8) / 16.

- Using the downstream time formula, substitute:

- For (X + 60) km: X + 60 = 5 * 16, giving X = 20 km.

- Using the upstream time formula, substitute:

- For (Y + 32) km: Y + 32 = 8 * 8, giving Y = 32 km.

- Substitute X and Y in (X + 3Y/8) to find the distance and calculate the time:

- X + 3Y/8 = 20 + 3(32)/8 = 20 + 12 = 32 km.

- Time = 32/16 = 2 hours.

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