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

Quantitative Aptitude

BOATS AND STREAMS MCQs

Total Questions : 948 | Page 95 of 95 pages

Question 941. The speed of a boat in still water is 2km/hr. If its speed upstream be 1km/hr then speed of the stream is________?

1.5km/hr
3km/hr
1km/hr
none

Discuss Question

Answer: Option C. -> 1km/hr
LET THE SPEED OF STREAM BE X KM/HR
SPEED UPSTREAM = (2-X) KM/HR = 2-X = 1 => X = 1 KM/HR

Question 942. A boat takes half time in moving a certain distance downstream than upstream. What is the ratio between the rate in still water and rate of current?

1 : 2
3 : 1
2 : 1
1 : 3

Discuss Question

Answer: Option B. -> 3 : 1
LET THE SPEED OF THE BOAT IN STILL WATER BE 4 KM/HR AND SPEED OF THE CURRENT BE U KM/HR.
RATE DOWNSTREAM = (U + V) KM/HR.
RATE UPSTREAM = (U- V)KM/HR
LET THE DISTANCE COVERED IN EACH CASE BE X KM.
THEN 2X/(U + V) = X / (U – V)
=> 2 (U – V) = ( U + V)
=> U =3V
=> U/V =3/1

Question 943. A man can row three-quarters of a kilometer against the stream in 11 ¼ minutes and return in 7 ½ minutes. The speed of the man in still water is________?

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

Discuss Question

Answer: Option D. -> 5 km/hr
DISTANCE COVERED UPSTREAM IN 45/4MIN =3/4 KM
DISTANCE COVERED UPSTREAM IN 1 HR =(3/4 × 2/15 × 60) KM/HR = 4 KM/HR
DISTANCE COVERED DOWNSTREAM IN 15/2 MIN = ¾ KM
DISTANCE COVERED DOWNSTREAM IN 1HR
= (3/4 × 2/15 × 60)KM/HR = 6 KM/HR
SPEED OF THE MAN IN STILL WATER
= ½ (6 + 4)KM/HR = 5 KM/HR

Question 944. A man can row 7 ½ kms on hour in still water and he finds that it takes hi twice as long to row down the river. The rate of stream is

2.4km/hr
2.5 km/hr
3.4km/hr
3.5km/hr

Discuss Question

Answer: Option B. -> 2.5 km/hr
LET THE RATE OF THE STREAM BE X KM/HR.
THEN SPEED DOWNSTREAM = (15/2 + X)KM/HR.
SPEED UPSTREAM = (15/2 -X)KM/HR
(15/2 + X) = 2 (15/2 – X)
=> 3X =15/2
=> X = 15/6 = 5/2 = 2.5
THEREFORE, RATE OF STREAM = 2.5 KM/HR

Question 945. A boat goes 6 km in an hour in still water. It takes thrice as much time in covering the same distance against the current. Speed of the current is_______?

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

Discuss Question

Answer: Option C. -> 4km/hr
SPEED IN STILL WATER = 6 KM/HR
SPEED AGAINST THE CURRENT = 6/3 KM/HR = 2 KM/HR
LET THE SPEED OF THE CURRENT BE X KM/HR
6-X = 2 => X =4 KM/HR

Question 946. In a river, a man takes 3 hours in rowing 3 km upstream or 15 km downstream. What is the speed of the current?

2km/hr
4km/hr
6km/hr
9km/hr

Discuss Question

Answer: Option A. -> 2km/hr
SPEED UPSTREAM = 3/3 KM/HR =1 KM/HR
SPEED DOWNSTREAM = 15/3 KM/HR = 5 KM/HR
SPEED OF CURRENT = ½(5 -1) KM/HR = 2 KM/HR

Question 947. A man can row at 5 km/hr in still water, if the river is running at 1 km/hr it takes him 75 minutes to row to a place and back. How far is the place?

2.5km
3km
4 km
5 km

Discuss Question

Answer: Option B. -> 3km
SPEED DOWNSTREAM = (5+1)KM/HR = 6 KM/HR
SPEED UPSTREAM = (5-1)KM/HR = 4 KM/HR
LET THE REQUIRED DISTANCE BE X KM.
THEN X/6 + X/4 = 75/60 = 5/4 => (2X + 3X) =15 => X =3.
REQUIRED DISTANCE = 3 KM

Question 948. A boat running upstream takes 8 hours 48 min 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 the speed of water current respectively?

2 : 1
3 : 1
8 : 3
Cannot be determined

Discuss Question

Answer: Option C. -> 8 : 3
LET THE SPEED OF BOAT BE X KM/HR AND SPEED OF STREAM BE YKM/HR.
44/5 × (X -Y) = 4X (X +Y)
=> 44(X-Y) = 20 (X+Y)
=>11 (X-Y) = 5 (X +Y)
=> 6X =16 Y
=> X/Y = 16/6 = 8/3
=> X : Y = 8 : 3