Study Material — 5 PYQs (2022–2022) · Concept Notes · Shortcuts
SBI PO Boats & Streams is a frequently tested subtopic — 5 previous year questions from 2022–2022 papers are included below with concept notes, key rules and shortcut tricks.
5 questions from actual SBI PO papers · all shown free · click option to reveal solution
Exam Q 12022Previous Year Pattern
A boat covers a certain distance downstream in 8 hours and the same distance upstream in 12 hours. If a person rows a boat at a speed of 15 km/h in still water, what is the distance?
Exam Q 22022Previous Year Pattern
A boat travels from point A to point B (downstream) in 5 hours and returns from B to A (upstream) in 7 hours. If the boat's speed in still water is 24 km/h, what is the distance between A and B?
Exam Q 32022Previous Year Pattern
A boat takes 10 hours to travel 120 km downstream. The ratio of the boat's speed in still water to the stream's speed is 7:1. How much time will the boat take to travel 120 km upstream?
Exam Q 42022Previous Year Pattern
A boat takes 4 hours to travel 60 km downstream and 5 hours to travel 50 km upstream. If the boat travels 84 km downstream and then immediately returns 84 km upstream, what is the total time taken (in hours)?
Exam Q 52022Previous Year Pattern
A boat travels 48 km downstream in 3 hours and 48 km upstream in 6 hours. A swimmer can swim at a speed equal to the boat's speed in still water. If the swimmer swims 32 km downstream, how long (in hours) will it take?
Concept Notes
Boats & Streams— Rules & Concept
Core ConceptRead this first — the foundation of the topic
Core Concept
Imagine walking on a moving escalator. If you walk in the same direction as the escalator, you move faster. If you walk against it, you move slower. Similarly, water current helps or hinders boat movement
Key Rules
Speed of boat in still water = (Downstream speed + Upstream speed) ÷ 2. Speed of current = (Downstream speed - Upstream speed) ÷ 2. Downstream speed = Boat speed + Stream speed. Upstream speed = Boat speed - Stream speed.
Formula BlockMemorise — at least one formula appears in every paper
• Downstream Speed = Speed in still water + Speed of stream
• Upstream Speed = Speed in still water - Speed of stream
• Speed in still water = (Downstream + Upstream) ÷ 2
• Speed of stream = (Downstream - Upstream) ÷ 2
• Time = Distance ÷ Speed
Exam PatternsWhat examiners ask — read before attempting PYQs
Questions typically ask for boat speed in still water, stream speed, time calculations, or distance problems. Common formats include round trips, meeting point problems, and comparative speed questions.
ShortcutsUse these to save 30–60 seconds per question
When distance is same upstream and downstream, use the harmonic mean formula: Average speed = (2 × Downstream speed × Upstream speed) ÷ (Downstream speed + Upstream speed).
Worked ExampleSolve this step-by-step before moving on
Apply formulas
Boat speed in still water = (10 + 4) ÷ 2 = 7 km/hr
Stream speed = (10 - 4) ÷ 2 = 3 km/hr
Worked Example 2: A man can row 6 km/hr in still water. Stream speed is 2 km/hr. How long to travel 16 km downstream and return?
Calculate times
Time downstream = 16 ÷ 8 = 2 hours
Time upstream = 16 ÷ 4 = 4 hours
Total time = 2 + 4 = 6 hours
Trick for Round Trips: Total time = Distance × 2 × Boat speed ÷ (Boat speed² - Stream speed²)
Exam TrapsCommon mistakes students make — avoid these
Students often confuse downstream and upstream directions. Remember: downstream means 'with the flow' (faster), upstream means 'against the flow' (slower). Another trap is adding stream speed when calculating upstream speed instead of subtracting it.
Always check if your downstream speed is greater than upstream speed.
A boat covers the same distance downstream in 4 hours as it covers upstream in 6 hours. If the stream's speed is 4 km/h, what is the boat's speed in still water?
Practice 2easy
A boat takes 5 hours to travel 60 km downstream and 8 hours to travel the same distance upstream. What is the speed of the stream?
Practice 3easy
A boat's speed in still water is 10 km/h and the stream's speed is 3 km/h. How long will it take the boat to travel 91 km upstream?
Practice 4easy
A man can row 36 km downstream in 4 hours. If his speed in still water is 8 km/h, what is the speed of the current?
Practice 5easy
A boat travels 48 km downstream in 3 hours. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?
Practice 6easy
A boat's speed in still water is 12 km/h and the stream's speed is 3 km/h. If the boat travels 45 km downstream and then returns to the starting point, what is the total time taken?
Practice 7medium
A boat's speed in still water is 8 km/h. It takes 2 hours to travel a certain distance downstream and 3 hours to travel the same distance upstream. What is the speed of the stream?
Practice 8medium
The speed of a boat in still water is 10 km/h and the speed of the stream is 2 km/h. How long will it take the boat to travel 60 km downstream and then return to the starting point?
Practice 9medium
A swimmer swims 24 km downstream in 2 hours and 24 km upstream in 4 hours. If he swims in still water for 6 hours, how far will he travel?
Practice 10medium
A man can row 30 km upstream in 6 hours. If the stream speed is 1 km/h, what is his speed in still water?
Practice 11medium
A boat takes 5 hours to travel 80 km downstream. The stream speed is 25% of the boat's speed in still water. How much time will the boat take to travel 60 km upstream?