Quantitative aptitude section of any Banking recruitment exam conducted by IBPS or SBI definitely has questions based on the topic: boat and stream. The topic is considered an extension of time, speed and distance questions that are a part of school level mathematics. However, at school level students are used to solving such questions by framing linear equations in one or even two variables. But, this proves to be quite time consuming and cumbersome in case of a competitive exam.
However, the most Reputed Bank Coaching Institute in Delhi suggests an approach which can make your life much easier. Followed carefully this approach will help you solve boat and stream questions quickly and efficiently.
First of all, you must become familiar with the terms Upstream & Downstream. These terms will be used extensively when dealing with such questions.
UPSTREAM: When a boat / person moves in a direction opposite to that in which the stream is flowing, then the boat / person is said to be going upstream.
DOWNSTREAM: When the boat / person and the stream move in the same direction, then it is said that the boat / person is going downstream.
NOTE (I) In case of downstream, the boat and the stream move in the same direction so their speeds are added together. (II) In case of upstream, the boat moves against the flow of the stream so the speed of the stream is subtracted from the speed of the boat.
- u = speed of the boat / man in still water
- v = speed of the stream / current / water / flow.
- Net Downstream (in same direction of flow) speed = u + v
- Net Upstream (against the flow) speed = u – v
Shortcut Trick – I
If a boat travels downstream from point A to point B & then returns upstream from point B to A,then its average speed during the journey =
Question – 1: A boat takes 4 hours for travelling downstream from point A to point B and coming back to point A upstream. If the speed of the stream is 2 kmph and the velocity of the boat in still water is 4 kmph, what is the distance between A and B?
Question – 2: A man can row at the speed of 5 kmph in still water. If the river flows at the speed of 1 kmph, it takes him 75 minutes to row to a place and come back. How far is the place in km?
Question – 3: The current of the stream runs at 1 kmph. A motor boat moves 35 km upstream and comes back to the start point in 12 hours. The speed of the motor boat in still water (in kmph) is.
Shortcut Trick – II
If time taken by a boat covering a certain distance in upstream = n times of the time taken by the boat covering the same distance in downstream
Question – 4: A man can row at the speed of 28/3 kmph in still water and finds that it takes him thrice as much time to row up than as to row down the same distance in the river. The speed of the current in kmph is
Question – 5: A river runs at 2 kmph. It takes a man twice as long to row up as to row down this river. The speed of the man in still water (in kmph) is
Question – 6: A man can row at the rate of 3 kmph in still water and he finds that it takes him twice as much time to row up than as to row down the same distance in the river. The speed of the water in kmph is:
Solution: 1 kmph
Question – 7: A boat covers a certain distance downstream in 1 hour, while it comes back in 11⁄2 hours. If the speed of the stream is 3 kmph, find the speed of the boat in still water.
Question – 8: A boat running upstream takes 8 hours 48 minutes to travel a given distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and the speed of the water current respectively?
After having gone through the short tricks explained above, you must attempt sufficient number of practice problems. This will reinforce the concepts that you have learnt here from the experts teaching at the center for Best IBPS Coaching in Delhi. Moreover, you must go through the past Bank PO/Clerk papers to have further understanding of the pattern and difficulty level of questions asked in the exam.
This article has been written from the perspective of candidates who are about to appear in aptitude exams conducted for recruitment in public sector banking and other Govt. jobs. For any comments, feedback and suggestions, you can write to email@example.com.