Boats and Streams- Aptitude Questions and Answers

View in English View in Hindi

If a man rows at 5 km/hr in still water and 3.5 km/hr against the current,then his rate along the current is ?

A)
8.5 km/hr

B)
6.5 km/hr

C)
6 km/hr

D)
4.25 km/hr


Correct Answer :

6.5 km/hr


Explanation :

If The speed of boat or boatman in calm water is u kmph and The speed of water or stream is v kmph, then:In water, the speed along with stream= (u + v) kmph

Speed of current = 5 - 3.5 = 1.5 km/hr.

So the speed of man along the current = 5 + 1.5 = 6.5 km/hr

The speed of a boat downstream is 15 km/hr and the speed of the stream is 1.5 km/hr. The speed of the boat upstream is ?

A)
13.5 km/hr

B)
16.5 km/hr

C)
12 km/hr

D)
8.25 km/hr


Correct Answer :

12 km/hr


Explanation :

If The speed of boat or boatman in calm water is u kmph and The speed of water or stream is v kmph, then:
Speed downstream= (u + v) kmph , In water, the speed along with stream
Speed upstream = (u - v) kmph ,In water, the speed against the stream

15= u + 1.5
⇒ u = 13.5

Speed upstream, u - v = (13.5 - 1.5) km/hr = 12 km/hr

A boat goes 14 km upstream in 56 minutes. The speed of stream is 2 km/hr. The speed of boat in still water is ?

A)
6 km/hr

B)
15 km/hr

C)
14 km/hr

D)
17 km/hr


Correct Answer :

17 km/hr


Explanation :

Speed upstream Speed(S) = Distance(d)/Time(t) = 14/56 km/min = 14*60/56 km/hr= 15 km/hr

If The speed of boat or boatman in still water is U kmph and The speed of water or stream is V kmph, then:
Speed upstream = (U - V) kmph ,In water, the speed against the stream
15 = U - 2
So speed of boat in still water , U = 17 km/hr

A man can row upstream 32 km in 4 hours. If the speed of current is 2 km/hr, find how much he can go downstream in 6 hours ?

A)
70 km

B)
72 km

C)
64 km

D)
81 km


Correct Answer :

72 km


Explanation :

Upstream Speed(S) = Distance(d)/Time(t) = 32/4 km/hr= 8 km/hr

If The speed of boat or boatman in still water is U kmph and The speed of water or stream is V kmph, then:
Speed upstream = (U - V) kmph
8 = U - 2
Speed of man in still water,U = 8 + 2 = 10 km/hr

Speed of man in downstream = (U + V) kmph = (10 + 2) = 12 km/hr
Now, man cover the distance in 6 hours = 12 * 6 = 72 km

A man can row upstream at 15 km/h and downstream at 21 km/h. The speed of water current of the river is ?

A)
8 km/h

B)
6 km/h

C)
3 km/h

D)
5 km/h


Correct Answer :

3 km/h


Explanation :

If the speed downstream is x kmph and the speed upstream is y kmph, then:
Rate of stream = 1/2 (x - y) kmph.

= 1/2(21 - 15) km/h
= 3 km/h

A man rows downstream 60 km and upstream 36 km, taking 4 hours each time. The speed of the man is :

A)
15 km/h

B)
16 km/h

C)
8 km/h

D)
12 km/h


Correct Answer :

12 km/h


Explanation :

If the speed downstream is x kmph and the speed upstream is y kmph, then:
Speed in still water = 1/2 (x + y) kmph.

x = 60/4 =15 km/h
y = 36/4 = 9 km/h
speed of the man = (15 + 9) / 2 = 12 km/h

The speed of a boat in still water is 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is?

A)
1.2 km

B)
1.8 km

C)
2.4 km

D)
3.6 km


Correct Answer :

3.6 km


Explanation :

Speed Downstream = (15 + 3) km/hr = 18 km/hr.

Distance travelled =(18 * 12 / 60 )hrs = 3.6 km

The speed of a boat in downstream is 12 km / h and in upstream is 8 km / h. The time taken by boat to cover 24 km in still water?

A)
2 hours

B)
3 hours

C)
2.4 hours

D)
1.2 hours


Correct Answer :

2 hours


Explanation :

If The speed of boat or boatman in still water is U kmph and The speed of water or stream is V kmph, then:
Speed upstream = (U - V) = 8 km/hr
Speed of man in downstream = (U + V) kmph = 12 km/hr

After solving above equations 2*U = 20 km/hr
speed of boat in still water is,U = 10 km/hr

Required time = 24 / 10 = 2.4 hr

Latest Updates

Simplification

By what number should we multiply -1/5 so that the product may be 9/25?

Profit and Loss

A person sells an article for Rs 550, gaining 1/10 of its cost price. Its gain percentage is.

Algebra

If 3x + 2y = 12 and xy = 6, then 9x2 + 4y2 = ______.

Volume and Surface Area

In a temple there are 25 cylindrical pillars. The radius of each pillar is 28cm and height 4m. The total cost of painting the curved surface area of pillars at the rate of Rs. 8 per m2 is:

Problems on Ages

After 12 years, I shall be 3 times as old as I was 4 years ago. My present age is:

Square and Cube Root

The smallest number by which 1100 must be multiplied so that the product becomes a perfect square is____.

Probability

What is the probability that a number selected from the numbers 1, 2, 3,…….,25 is a prime number, when each of the given numbers is equally likely to be selected?

Square and Cube Root

What is the smallest number by which 3087 must be divided so that the quotient is a perfect cube?

Physics

The most comfortable distance at which one can read with a normal eye is:

Biology

Cholera is caused by:

Write the name of reptile with four chambered heart?

Compound Interest

Raj borrowed Rs. 5000 at 10% per annum on simple interest and lent the same amount at 15% per annum on compound interest. At the end of 2 years, he would ?

Area

If the area of a square is 16 cm2, then the area of the square joining the mid-points of the sides is?

General Knowledge of MP

Vidisha is situated on the banks of river?

General Knowledge of World

When is the Human Rights Day celebrated?

Profit and Loss

By selling coconuts at the rate of Rs. 6/- each, a trader gained 20%. Find the cost of 100 coconuts?

General Knowledge of India

How many coastal state are in India?

Numbers

A person is to count 4500 currency notes. Let an denote the number of notes he counts in the nth minute. If a1 = a2 = .... = a10 = 150 and a10 , a11 ,... are in an AP with common difference – 2, then the time taken by him to count all notes is ?