Boats And Streams(Quantitative Aptitude ) Questions and answers for exam Preparation

Quantitative Aptitude

BOATS AND STREAMS MCQs

Total Questions : 948 | Page 2 of 95 pages

A boat takes 90 minutes less to travel 36 miles downstream than to travel the same distance upstream. If the speed of the boat in still water is 10 mph , Find the speed of the stream .

2 mph
3 mph
4 mph
5 mph

Discuss Question

Answer: Option A. -> 2 mph

Question 12.

In one hr , a boat goes 11 km along the stream and 5 km againnt the stream. The speed of the boat in stiil water ( in km / hr ) is :

Discuss Question

Answer: Option C. -> 8

Question 13.

A man can row three-quarters of the a kilometer against the stream in 11 1/2 minutes . the speed ( in km/hr ) of the man in stiil water is :

Discuss Question

Answer: Option D. -> 5

Question 14.

If a boat goes 7 km upstream in 42 min and the speed of the stream is 3 km/hr, then the speed ( in km/hr)of the boat in stiil water is :

Discuss Question

Answer: Option B. -> 13

Question 15.

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 2 min. is :

1.2 km
2.4 km
3.6 km
none of these

Discuss Question

Answer: Option C. -> 3.6 km

Question 16.

The speed of a boat in steel in still water is 10 km/hr . If it can travel 26 km downs stream and 14 km upstream in the same time , the speed of the stream is :

2 km/hr
3 km/hr
4 km/hr
5 km/hr

Discuss Question

Answer: Option B. -> 3 km/hr

Question 17.

A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream.

2 hours
3 hours
4 hours
5 hours

Discuss Question

Answer: Option C. -> 4 hours

Speed downstream = (13 + 4) km/hr = 17 km/hr.

Time taken to travel 68 km downstream = \(\left(\frac{68}{17}\right)hrs = 4hrs.\)

Question 18.

A mans speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The mans speed against the current is:

8.5 km/hr
9 km/hr
10 km/hr
12.5 km/hr

Discuss Question

Answer: Option C. -> 10 km/hr

Man's rate in still water = (15 - 2.5) km/hr = 12.5 km/hr.

Man's rate against the current = (12.5 - 2.5) km/hr = 10 km/hr.

Question 19.

A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?

2 : 1
3 : 2
8 : 3
Cannot be determined
None of these

Discuss Question

Answer: Option C. -> 8 : 3

Let the man's rate upstream be x kmph and that downstream be y kmph.

Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.

\(\left(x\times8\frac{4}{5}\right) = (y\times4)\)

\(\frac{44}{5}x = 4y\)

\(y= \frac{11}{5}x\)

So, Required ratio = \(\left(\frac{x+y}{2}\right):\left(\frac{x-y}{2}\right)\)

\(\left(\frac{16x}{5}\times\frac{1}{2}\right) :\left(\frac{16x}{5}\times\frac{1}{2}\right)\)

\(\frac{8}{5}:\frac{3}{5}\)

= 8:3

Question 20.

A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:

Discuss Question

Answer: Option B. -> 5

Let the speed of the stream be x km/hr. Then,

Speed downstream = (15 + x) km/hr,

Speed upstream = (15 - x) km/hr.

So, \(\frac{30}{(15+x)}+\frac{30}{(15-x)}=4\frac{1}{2}\)

\(\frac{900}{(225-x^{2})}= \frac{9}{2}\)

9x² = 225

x² = 25

x = 5 km/hr.