SSC CGL Maths Arithmetic Boat & Stream by Ravinder Sir

SSC CGL Maths Arithmetic includes many important topics, and Boat and Stream is one of the most frequently asked concepts in competitive exams. Questions from this topic are based on speed, time, distance, river flow, upstream, and downstream movement.

To help students strengthen their understanding, this section covers important Boat and Stream practice questions based on key exam concepts. Students who want detailed solutions and step-by-step explanations of these questions can watch the attached video for complete guidance and concept clarity.

What is Boat and Stream?

Boat and Stream is a topic of Arithmetic. It is based on the movement of a boat, swimmer, or steamer in water. The water may be still, or it may be flowing in a certain direction. When a boat moves in a river, two speeds are involved. One is the speed of the boat in still water. The other is the speed of the stream. Still water means water that is not flowing. Stream means flowing water. In Hindi, a stream is called धारा.

Important Terms in Boat and Stream

Students should understand some basic terms before solving questions.

Still Water

Still water means water that has no movement. The speed of the boat in still water is the actual speed of the boat. It is usually represented as x km/hr.

Stream

Stream means the flow of water in a river. It is also called current or river water speed. It is usually represented as y km/hr.

Downstream

When a boat moves in the direction of the stream, it is called downstream. In this case, the stream helps the boat move faster. Downstream Speed = x + y

Upstream

When a boat moves against the direction of the stream, it is called upstream. In this case, the stream reduces the speed of the boat. Upstream Speed = x - y

Basic Formula of Boat and Stream

• Speed of boat in still water = (Downstream Speed + Upstream Speed) / 2

• Speed of stream = (Downstream Speed - Upstream Speed) / 2

These formulas are useful when downstream and upstream speeds are already given.

Concept of Direction in Boat and Stream

Direction plays an important role in this topic. If the boat and stream move in the same direction, their speeds are added. This is called downstream.

If the boat moves against the stream, the speed of the stream is subtracted from the speed of the boat. This is called upstream.

Students should first identify whether the question is based on upstream or downstream. After that, they can apply the formula.

Time, Speed, and Distance in Boat and Stream

Boat and Stream questions also use the basic formula of Time, Speed, and Distance.

• Speed = Distance / Time

• Distance = Speed × Time

• Time = Distance / Speed

For example, 48 minutes = 48/60 hours. This conversion is important because many mistakes happen when students directly use minutes with km/hr.

SSC CGL Maths Arithmetic Boat & Stream Practice Questions

After understanding the basic concepts of Boat and Stream, students should practise different types of questions. The questions below were discussed by Ravinder Sir and cover upstream, downstream, speed calculation, time conversion, ratio-based concepts, and stream speed problems.

Question 1: If the speed of a swimmer is 9 km/hr in still water and the speed of the stream is 5 km/hr, then find the speed of the swimmer against the stream and along the stream.

(a) 4 km/hr, 10 km/hr

(b) 4 km/hr, 14 km/hr

(c) 14 km/hr, 16 km/hr

(d) 14 km/hr, 18 km/hr

Question 2: The speed of a boat when travelling downstream is 32 km/hr, whereas when travelling upstream it is 28 km/hr. What is the speed of the boat in still water and the speed of the stream?

(a) 29 km/hr, 3 km/hr

(b) 30 km/hr, 2 km/hr

(c) 30 km/hr, 8 km/hr

(d) 31 km/hr, 1 km/hr

Question 3: A boat takes 48 minutes to cover 12 km against the stream. If the speed of the stream is 2 km/hr, then what will be the speed of the boat in still water?

(a) 17 km/hr

(b) 15 km/hr

(c) 13 km/hr

(d) 1.25 km/hr

Question 4: A man wishes to cover a 1 km distance in the river water. In still water, he takes 12 minutes to cover it, but in the flowing river, he takes 13 minutes. The speed of the flowing water of the river is:

(a) 25 km/hr

(b) 5/13 km/hr

(c) 22 km/hr

(d) 7/12 km/hr

Question 5: A boat covers a certain distance downstream in 2 hours, while it comes back in 2½ hours. If the speed of the stream is 3 km/hr, then what is the speed of the boat in still water?

(a) 29 km/hr

(b) 25 km/hr

(c) 20 km/hr

(d) 27 km/hr

Question 6: A swimmer walks 30 km along the flow of the river in 3 hours 45 minutes and walks 15 km against the flow in 2 hours 30 minutes. Find the speed of the boat in still water and the speed of flow (in km/hr).

(a) 8 and 1

(b) 7 and 8

(c) 7 and 1

(d) 9 and 10

Question 7: A boat moves downstream at the rate of 1 km in 7½ minutes and upstream at the rate of 5 km an hour. What is the speed of the boat in still water?

(a) 2 km/hr

(b) 6½ km/hr

(c) 4 km/hr

(d) 3½ km/hr

Question 8: A boat goes downstream in one-third the time it takes to go upstream. Then, the ratio between the speed of the boat in still water and that of the stream is:

(a) 3:1

(b) 1:3

(c) 1:2

(d) 2:1

Question 9: The speed of a boat in still water is 5⅓ km/h. It is found that the boat takes thrice as much time to row up than it does to row down the same distance in the river stream. Find the speed of the river stream.

(a) 23/27 m/sec

(b) 22/27 m/sec

(c) 20/27 m/sec

(d) 19/27 m/sec

Question 10: The speed of the boat in still water is thrice the speed of the stream. If it takes 6 hours to go 48 km against the stream, then what is the speed of the boat in still water in kilometers per hour?

(a) 10

(b) 8

(c) 12

(d) 14

SSC CGL Maths Arithmetic Boat & Stream by Ravinder Sir focused on building the concept from the ground level.

If you are preparing for SSC CGL, you should practise these questions regularly. They should first identify the direction of movement and then apply the correct formula. With regular practice, Boat and Stream questions can be solved quickly and accurately in the exam.