WBCS.LIVE practice question

In still water the actual speed of a boat is 10 Km./hr. and the speed of the river-current is 4 km./hr. What time will it take to cover a distance of 30 km. against the current?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. 2 hrs.
  2. 3 hrs.
  3. 4 hrs.
  4. 5 hrs.

Correct answer and explanation

Correct answer: 5 hrs.

Explanation: āœ… Correct Answer: D. 5 hrs. šŸ“š Explanation: When a boat moves against the current (upstream), its speed is the boat speed minus the stream speed. Here, the net speed is 10 - 4 = 6 km/hr. To cover a distance of 30 km at a speed of 6 km/hr, we divide 30 by 6. This calculation gives exactly 5 hours for the journey.