Boat and Stream is a classic topic in Quantitative Aptitude that frequently appears in competitive exams like SSC, Banking, RRB, and State PSC exams. In this blog, we have provided all the detailed short notes, formulas, quick tricks, solved questions from 2024–25 exams, and more.
What Is Boat and Stream in Quantitative Aptitude?
Boat and Stream problems involve calculating speed, distance, and time when a boat is moving in a river either with the current (downstream) or against the current (upstream).
- Upstream Speed = Boat Speed (x) – Stream Speed (y)
- Downstream Speed = Boat Speed (x) + Stream Speed (y)
Why it appears in exams:
- Tests speed and distance concepts.
- Evaluates logical thinking and calculation accuracy.
- Commonly asked in SSC, Banking, and RRB exams.
Skills required:
- Logical reasoning
- Basic arithmetic calculations
- Speed, distance, and time problem-solving
- Analytical thinking
Why Is Boat and Stream Important in Competitive Exams?
Boat and Stream questions are relatively easy to score if you know the formulas and shortcuts. Most exams include 1–2 questions from this topic.
| Exam | No. of Questions | Difficulty |
| SSC CGL / CHSL | 1–2 | Easy |
| IBPS PO / SBI PO | 1–2 | Moderate |
| RRB NTPC / Group D | 1 | Easy |
| State PSC / Police | 1–2 | Moderate |
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Boat and Stream Quantitative Aptitude Short Notes
Some of the basic concepts related to the topic boat and stream are as follows:
| Concept | Details |
| Boat Speed (B) | Speed of boat in still water |
| Stream Speed (S) | Speed of river/stream |
| Upstream Speed | B – S/x-y |
| Downstream Speed | B + S/x+y |
| Time Formula | Time = Distance ÷ Speed |
| Distance Formula | Distance = Speed × Time |
| Relative Speed | Difference of speeds when two objects move in opposite directions |
| Average Speed | Total Distance ÷ Total Time |
Quick Revision Summary
A quick table for last-minute revision:
| Concept | Explanation |
| Upstream Speed | Boat Speed – Stream Speed |
| Downstream Speed | Boat Speed + Stream Speed |
| Time Formula | Time = Distance ÷ Speed |
| Distance Formula | Distance = Speed × Time |
| Relative Speed | Difference of speeds (opposite direction) |
| Average Speed | Total Distance ÷ Total Time |
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Main Concept related to Boat and Stream
Boat and Stream questions are generally categorized by the unknown variable you need to calculate: time, speed, or distance. All problems are based on the upstream and downstream motion, where the speed of the river either aids or opposes the boat’s motion.
Main Concepts
- Speed of the boat in still water (uuu) – Velocity of the boat when there is no current.
- Speed of the stream (vvv) – Velocity of the water flow.
- Downstream speed: Boat moves with the current → u+vu + vu+v
- Upstream speed: Boat moves against the current → u−vu – vu−v
What Are the Types of Boat and Stream Questions in Quantitative Aptitude?
There are several types of questions that were being asked from the topic of boat and stream, the details of the questions are as follows:
- Time-based questions
These problems ask how long it takes to cover a distance upstream or downstream. Example: A boat moves at 12 km/hr in still water. If the stream flows at 4 km/hr, how long will it take the boat to travel 32 km upstream?
Solution:
Upstream speed = 12 – 4 = 8 km/hr
Time = Distance ÷ Speed = 32 ÷ 8 = 4 hours
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- Speed-based questions
These questions require finding the speed of the boat in still water or the speed of the stream. Example: A boat goes 18 km downstream in 2 hours and 12 km upstream in 3 hours. Find the boat’s speed in still water.
Solution:
Downstream speed = 18 ÷ 2 = 9 km/hr
Upstream speed = 12 ÷ 3 = 4 km/hr
Boat speed = (9 + 4)/2 = 6.5 km/hr
- Distance-based questions
Here, the task is to find the distance traveled using given speeds and times. Example: A boat rows at 10 km/hr in still water. The river flows at 2 km/hr. It takes 2 hours more to go upstream than downstream. Find the distance traveled.
- Ratio-based questions
These involve the ratio of boat speed to stream speed to find distance, time, or speed. Example: The ratio of boat speed to stream speed is 5:1. A boat travels 60 km downstream in 4 hours. Find the distance it can cover upstream in 3 hours.
Solution:
Let boat speed = 5x, stream speed = x
Downstream speed = 5x + x = 6x → 6x = 60 ÷ 4 = 15 → x = 2.5 km/hr
Upstream speed = 5x – x = 4x = 4 × 2.5 = 10 km/hr
Distance upstream in 3 hours = 10 × 3 = 30 km
- Round-trip / Average speed questions
These involve a journey to a point and returning to the start. Example: A boat covers 24 km downstream and returns to the starting point. Boat speed = 8 km/hr, stream speed = 2 km/hr. Find total time for the trip.
Solution:
Downstream speed = 8 + 2 = 10 km/hr → Time = 24 ÷ 10 = 2.4 hr
Upstream speed = 8 – 2 = 6 km/hr → Time = 24 ÷ 6 = 4 hr
Total time = 2.4 + 4 = 6.4 hr
Boat and Stream Formulas for Quantitative Aptitude
Key formulas for fast calculations:
Boat and Stream Tricks for SSC CGL and Other Exams
Some tricks to keep in mind while solving Boat and Stream questions, as these questions may be asked in a tricky format:
- Always identify upstream and downstream first.
- Convert all units to km/h or m/min before solving.
- Use formulas to find stream speed or boat speed when missing.
- For average speed problems, use total distance ÷ total time directly.
- Draw a small diagram of the river and boat for visualization.
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Solved Boat and Stream Questions from 2024–25 Exams
1. SSC CGL 2024 Tier 1 – Shift 2 (Memory-Based)
Question: A boat covers 24 km downstream in 3 hours and the same distance upstream in 4 hours. Find the speed of the boat in still water.
Answer: 5.25 km/h
Explanation:
Downstream speed = 24 ÷ 3 = 8 km/h
Upstream speed = 24 ÷ 4 = 6 km/h
Boat speed = (8 + 6)/2 = 7 km/h
Stream speed = (8 – 6)/2 = 1 km/h
2. IBPS PO Prelims 2024
Question: A boat goes 15 km downstream in 2 hours and returns upstream in 3 hours. Find the stream speed.
Answer: 1.5 km/h
Explanation:
Downstream = 15 ÷ 2 = 7.5 km/h
Upstream = 15 ÷ 3 = 5 km/h
Stream speed = (7.5 – 5)/2 = 1.25 km/h
3. RRB NTPC 2024
Question: A boat takes 2 hours more to go 24 km upstream than downstream. If the speed of the boat in still water is 6 km/h, find the speed of the stream.
Answer: 2 km/h
Explanation: Use T=D/(B±S)T = D/(B ± S)T=D/(B±S), solve equation 24/(6–S)–24/(6+S)=224/(6 – S) – 24/(6 + S) = 224/(6–S)–24/(6+S)=2
Boat and Stream Concepts for Bank Exams
In IBPS or SBI exams, boat and stream problems often appear in coded or logic-tree formats, e.g., representing downstream as A → B, upstream as B → A.
Example: A boat moves downstream from X to Y in 4 hours, coded as “XY = 4 units.” Use formula conversion for speed and distance.
Common Mistakes to Avoid while Solving Boat and Stream
Some of the common mistakes to avoid while solving questions based on boat and stream are as follows:
- Confusing upstream and downstream: Always note the direction.
- Unit mismatch: Convert time and distance to same units.
- Skipping diagrams: Leads to wrong speed calculations.
- Wrong formula application: Double-check formulas before solving.
- Rushing complex questions: Take a few seconds to analyze before solving.
Related Quantitative Aptitude Topics to Explore
Aspirants, as of now, you have an idea about how to solve and practice Boat and Stream questions. You can also join Oliveboard courses and learn from expert faculties before applying for the next competitive exam.
FAQs
Use the formulas for upstream and downstream speed and visualize the problem.
Always convert to km/h or m/min depending on the problem.
Yes, they may use letters/symbols for stream and boat speeds.
Sometimes; convert to decimals for ease.
Yes, it falls under Speed, Distance, and Time.
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