# 20 + Boats and Streams Questions and Answers | Quantitative Aptitude⬇️📝

Boats and streams questions are the mathematical questions that come into various competitive exams like quantitative aptitude section of major government exams. To excel these questions in an examination, practicing them is the key. Here are some questions to help you practice and develop a group on them to ace the examination.

## Important Formulas📝

If the speed of a boat in still water is x km/h and the speed of the stream is y km/h, then

• Downstream speed (v) = (x + y) km/h
• Upstream speed (u) = (x-y) km/h

From this relationship, we can say that

• Speed of Boat in still water = (u + v) / 2 km/h
• Speed of Steam = (v – u) / 2 km/h

## Boats and Streams Questions and Answers 📝

Below are the boats and streams questions with answers to help you practice them and ace at the examination.

Q 1. A person can swim in water with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, what will be the time taken by the person to go 68 km downstream?

2.5 hours
3 hours
4 hours
3.5 hours
4.5 hours

Solution:
Downstream Speed = (13+4) km/hr = 17 km/hr
To travel 68 km downstream.
Time taken = 68/17 = 4 hours

Q 2. In one hour, a boat goes 13 km/hr in the direction of the stream and 7 km/hr against the direction of the stream. What will be the speed of the boat in still water?

8 km/hr
10 km/hr
14 km/hr
6 km/hr
Cannot Be Determined

Solution:
According to the formula,
Speed of a boat in still water = ½ (DownstreamSpeed + UpstreamSpeed)
Speed of boat in still water = ½ (13+7) = ½ × 20 = 10 km/hr

Q 3. A woman can row upstream at 16 km/hr and downstream at 26 km/hr. What is the speed of the stream?

5 km/hr
2 km/hr
4.5 km/hr
21 km/hr

Solution:
According to the formula,
Speed of the stream = ½ (Downstream Speed – Upstream Speed)
Speed of the stream = ½ (26-16) = ½ × 10 = 5 km/hr

Q 4. A speedboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. What is the speed of the stream in km/hr?

2.5 km/hr
3.5 km/hr
4 km/hr
5 km/hr
3.25 km/hr

Solution:
Let the speed of the stream be x km/hr
Upstream Speed = 15 + x
Downstream Speed = 15 – x
So, {30 / (15+x)} + {30 / (15-x)} = 4 ½ (4 hours 30 minutes)
⇒ {900 / (225-x2)} = 9/2
⇒ 9x2 = 225
⇒x2 = 25
⇒x = 5

Q 5. A boat is moving 2 km against the current of the stream in 1 hour and moves 1 km in the direction of the current in 10 minutes. How long will it take the boat to go 5 km in stationary water?

1 hr 20 minutes
1 hr 30 minutes
1 hr 15 minutes
30 minutes
45 minutes

Answer: (3) 1 hr 15 minutes
Solution:
Downstream = (1/10 × 60) = 6 km/hr
Upstream = 2 km/hr
Speed in still water = ½ (6+2) = 4 km/hr
So, the time is taken by the boat to go 5km in stationary water = 5/4 hrs = 1 ¼ hrs = 1 hr 15 minutes

Q 6. A boat takes 27 hrs to travel a distance upstream and takes 9hrs to travel the same distance downstream. If the speed of the boat in still water is 12km/hr, then what is the velocity of the stream?

4km/hr
6km/hr
8km/hr
10km/hr

Ans : B
Explanation: Let the velocity of the stream be y km/hr
Then the speed of the downstream = (12 + y)km/hr
The speed of the upstream = (12 – y)km/hr
9 (12 + y) = 27 (12 – y)
108 + 9y = 324 – 27y
27y + 9y = 324 – 108
36y = 216
y = 6 km/hr

Q 7. A boat covers 12 km upstream and 18km downstream in 3hrs while it covers 18 km upstream and 12km downstream in 3(1/4) hrs the velocity of the the boat upstream and downstream?

12km/hr
14km/hr
16km/hr
18km/hr

Ans : A
Explanation: Let rate of upstream be ‘x’km/hr and downstream be ‘y’ km/hr
Then, 12/x + 18/y = 3 –>1
18/x + 12/y =13/4 –>2
Adding 1 and 2 we get,
30/x + 30/y = 25/4
1/x + 1/y +=5/24 –>3
Subtracting 1 and 2 we get
1/x – 1/y = 1/24 –>4
Adding 3 and 4 we get,
2/x = 6/24 ; x= 8 ->5
Substitute 5 in 3 we get, y=12
Speed of upstream = 8 km/hr and downstream = 12 km/hr

Q 8. If a boy rows 8 km downstream in 6 hours and 4 km upstream in 4 hours then how long will he take to cover 16 km in stationary (still) water?

8
14
22
16

Ans : B
Explanation: Distance covered in downstream = 8 km
Time taken in downstream = 6 hours.
Rate of downstream = 8/6=4/3 km/hr
Distance covered in upstream = 4 km
Time taken in upstream = 4hours.
Rate of upstream = 4/4 = 1 km/hr
Speed in still water = (1/2)(4/3+1) = 7/6km/hr
Time Taken to cover 16 km in still water = 16*6/7=14hrs (approximately)

Q 9. A boat takes 24 hours to cover 128 km downstream and 16 hours to cover 64 km upstream. Then the speed of the boat in still water is:

14/3
8/7
3/2
9/5

Explanation: Distance covered in downstream = 128km
Time taken in downstream = 24 hours.
Rate of downstream = distance / time = a = 128 km /24 hours = 16/3km/hr
Distance covered in upstream = 64km
Time taken in upstream = 16 hours.
Rate of upstream = distance / time = b = 64km /16hours = 4 km/hr.
Speed in still water = (a + b) / 2 = (1/2)(16/3+4) km/hr = (1/2)(28/3)km/hr
= 14/3km/hr

Q 10. A pedal boat goes 12km upstream and 14km downstream in 3hrs. It goes 15km upstream and 10.5km downstream in 3 hrs 15mints. The speed of the boat in still water is:

10
15
20
25

Ans : A
Explanation: Let ‘x’ be the speed of the boat in still water
Let ‘y’ be the speed of the current.
Pedal boat will travel downstream at (x + y)km/hr and upstream (x – y)km/hr
Therefore 14/x +y + 12/ x –y = 3
10.5/(x+y) + 15/(x-y) = 13/4
70/(x+y) +60 /(x-y) =15 –>1
42 /(x+y) + 60/(x-y) = 13 –>2
From 1 and we get,
x+y = 14 ; x-y = 6
Therefore x= 10 ; y = 4
The speed of the pedalboat is 10 km/hr

Q 11. A boat man lakes 5hrs 30 mins to row a boat 30km downstream of a river and 4 hrs 15mints to cover a distance of 10km upstream. Find the speed of the river current in km/hr.

1kmph
1.5kmph
2.0kmph
2.5kmph

Ans : B
Explanation: Rate downstream = 30 / (11/2) km/hr
= 30 * 2 / 11 km/hr
= 60/11 km/hr
Rate upstream = 10 / (17/4)km/hr
= 10 * 4 / 17 km/hr
= 40 / 17 km/hr
Speed of current = 1 / 2 (a – b) km/hr
=1 / 2 (60 / 11 – 40 / 17)
= 1.5 km/hr (approx.)

Q 12. A man can row 4 km against the stream in 40mins and return in 36mins. Find the rate of current.

1/3kmph
2/3kmph
4/3kmph
5/3kmph

Ans : A
Explanation: Speed of the man (upstream) = (4 / 40 * 60) km/hr
= 6 km/hr
Speed of the man (downstream) = ( 4 / 36 * 60) km/hr
= (60 / 9)km/hr
= 20/3 km/h
Rate of the current = ½[downstream speed – upstream speed]
= (1/2) [ 20 / 3 – 6] km/hr
Rate of the current = 1/3 km/hr

Q 13. Sakthi rows a boat at 4 km upstream in 1hour and 1 km downstream in 20 minutes. How long will he take to reach 3.5km in still water?

1
2
3
4

Ans : A
Explanation: Upstream Speed = 4/1 = 4km/hr
Downstream Speed = 1/20 = 0.05 km/min
= 0.05*60 = 3 km/hr
Hence, speed of boat = 1/2( Upstream Speed + Downstream Speed)
= 1/2 (4+3)km/hr =3.5 km/hr
Thus, the time required to reach the distance of 3.5 km=DistanceCovered/Speed of boat
= 3.5/3.5km/hr =1 km/hr

Q 14. A motor boat sails 30 km of a river towards upstream in 10hrs. How long will it take to cover the same distance downstream, if the speed of the current is ½ of the speed of the boat in still water.

8hr
3.33hr
5hr
4.33hr

Ans : B
Explanation: Upstream speed = x –y
Downstream speed = x + y
x– y = 30/10 = 3km/hr
Again x = 2y
Therefore x – y = 3
y= 3km/hr ; x = 6km/hr
Therefore x + y = 9 km/hr
Time during downstream = 30/9 = 3.33hrs

Q 15. Vinny can row 15km/h in still water and it takes twice as long to row up the stream than to row down. Find the rate of the stream.

1.8 km/hr
3.33 km/hr
5 km/hr
33 km/hr
Solution- 5km/h
The ratio between downstream and upstream speed = 2:1
Let the upstream speed be 2x, then the speed downstream will be x
Speed is still water = (v+u) / 2 = (2x + x) / 2 = 3x/2 = 15 (given)
Hence, x = 10 km/h
Speed of stream = (v-u)/2 = (20-10)/2 = 5 km/h

16. Mohana can row 80km upstream and 110km downstream in 26 hrs. Also she can 60km upstream and 88km downstream in 20 hrs. Find the speed of the girl in still water and the speed of the current in ratio:

5:6
3:7
7:9
8:3

Ans : D
Explanation: Let rate upstream = ‘x’ km/hr and
Rate downstream = ‘y’ km/hr
Then 80/x + 110/y = 26 —>1
60/x + 88/y = 20–>2
By solving 1 and 2
y= 11 ; x = 5
Rain in still water = (1/2) (11 + 5) km/hr = 8 km/hr
Rain of current = (1/2) (11 – 50) km/hr = 3 km/hr

17. A motorboat running upstream takes 4 hrs 24 mins to cover a certain distance, while it takes 2hrs to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?

8:3
5:2
3:7
2:4

Ans : A
Explanation: Let the man’s rate upstream be ‘x’ km/hr and downstream be ‘y’ km/hr
Then distance covered upstream by 4hrs 24mints = distance covered by downstream in 2hrs
(x * 4 2/5) = y *2
22x/5 = 2y
Y = 11x/5
Required ratio = (y+x/2) : (y –x/2)
= 16x/10 : 6x/10
= 16x : 6x
= 8:3

18. A person can swim in water with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, what will be the time taken by the person to go 68 km downstream?

1hr
2hr
3hr
4hr

Ans : D
Explanation: Downstream Speed = (13+4) km/hr = 17 km/hr
To travel 68 km downstream.
Time taken = 68/17 = 4 hours

19. In one hour, a boat goes 13 km/hr in the direction of the stream and 7 km/hr against the direction of the stream. What will be the speed of the boat in still water?

10km/hr
20km/hr
30km/hr
40km/hr
Ans : A
Explanation: According to the formula,
Speed of a boat in still water = (1/2) (DownstreamSpeed + UpstreamSpeed)
Speed of boat in still water = (1/2) (13+7) = (1/2) × 20 = 10 km/hr

20. A woman can row upstream at 16 km/hr and downstream at 26 km/hr. What is the speed of the stream?

1km/hr
5km/hr
3km/hr
9km/hr

Ans : B
Explanation: According to the formula,
Speed of the stream = (1/2)(Downstream Speed – Upstream Speed)
Speed of the stream = (1/2)(26-16) = (1/2) × 10 = 5 km/hr

## FAQs

How do you solve Boats and Streams problems in aptitude?

Firstly read and analyse the questions two-three times before attempting to solve them on your examination asnwer sheet.

In which exam does Boats and Streams Questions come?

There are various exams like quantitative aptitude section of major government exams such as IBPS PO, IBPS Clerk, SBI PO, SBI Junior Associate, RRB Clerk, RRB Scale 1 Officer, SSC CGL, SSC CHSL, LIC Assistant, etc in which these types of questions actually comes in.

Is this tuff to solve these types of problems?

No by using common sense and correct formulas you can easily solve these types of questions.

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