Online exam in Boat and Stream For Quantitative Aptitude for Competitive exams like IBPS BANK PO/Clerical,SBI,RRB,SSC,LIC,UPSC-CSAT,SCRA.MAT,CMAT,MBA,SNAP,CAT,NTSE,CLAT
Boat and Stream-Test 4
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Subject :- Quantitative Aptitude
Chapter :- Boat and Stream-Test 4
Questions :- 25
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A boat covers a certain distance downstream in 2 hour, while it comes back in 2 1/2 hours. If the speed of the stream be 5 kmph, what is the speed of the boat in still water?
Correct
Let the speed of the boat in still water be x kmph. Then,
Speed downstream = (x + 5) kmph,
Speed upstream = (x – 5) kmph.
(x + 5)*2 = (x – 5)*5/2
X = 45 kmph
Incorrect
Let the speed of the boat in still water be x kmph. Then,
Speed downstream = (x + 5) kmph,
Speed upstream = (x – 5) kmph.
(x + 5)*2 = (x – 5)*5/2
X = 45 kmph
Question 2 of 25
2. Question
1 points
A boat running downstream covers a distance of 40 km in 5 hrs and for covering
the same distance upstream it takes 10 hrs. What is the speed of the stream?
Correct
Downstream speed = 40/5 = 8 km/hr
Upstream speed = 40/10 = 4 km/hr
So speed of stream = 1/2*(8-4)
=2 km/hr
Incorrect
Downstream speed = 40/5 = 8 km/hr
Upstream speed = 40/10 = 4 km/hr
So speed of stream = 1/2*(8-4)
=2 km/hr
Question 3 of 25
3. Question
1 points
A boat goes 4 km against the current of the stream in 1 hour and goes 1 km along the
current in 10 minutes. How long will it take to go 15 km in stationary water?
Correct
Rate downstream = 1/10 * 60 = 6kmph
Rate upstream = 4 km/hr.
Speed in still water = ½ * 10 = 5 kmph
Required time = 15/5 = 3 hr
Incorrect
Rate downstream = 1/10 * 60 = 6kmph
Rate upstream = 4 km/hr.
Speed in still water = ½ * 10 = 5 kmph
Required time = 15/5 = 3 hr
Question 4 of 25
4. Question
1 points
A man rows to a place 40 km distant and come back in 9 hours. He finds that he can
row 5 km with the stream in the same time as 4 km against the stream. The rate of the
stream is:
Correct
Speed downstream = 5/x
Speed upstream = 4/x
40/(5/x) + 40/(4/x) = 9
X = ½
So, Speed downstream = 10 km/hr, Speed
upstream = 8 km/hr.
Rate of the stream = 1/2 * 2 = 1 kmph
Incorrect
Speed downstream = 5/x
Speed upstream = 4/x
40/(5/x) + 40/(4/x) = 9
X = ½
So, Speed downstream = 10 km/hr, Speed
upstream = 8 km/hr.
Rate of the stream = 1/2 * 2 = 1 kmph
Question 5 of 25
5. Question
1 points
A man can row 8 km/hr in still water. When the river is running at 4 km/hr, it takes
him 2 1/3 hr to row to a place and come back. How far is the place?
Correct
Downstream speed = 8+4= 12 => a
Upstream speed = 8-4= 4 => b
Distance = a*b/(a+b) * total time (t)
= 12*4/16 * 7/3
= 7kms
Incorrect
Downstream speed = 8+4= 12 => a
Upstream speed = 8-4= 4 => b
Distance = a*b/(a+b) * total time (t)
= 12*4/16 * 7/3
= 7kms
Question 6 of 25
6. Question
1 points
A boat can travel 15 km downstream in 18 min. The ratio of the speed of the boat in still
water to the speed of the stream is 4 : 1. How much time will the boat take to cover 10 km upstream?
Correct
B = [tu + td] / [tu – td] * R
15 km downstream in 18 min so 10 km in
(18/15)*10 = 12 min
B= 4x, R = x
Now
4x = [tu + 12] / [tu – 12] * x
Solve, tu = 20 min
Incorrect
B = [tu + td] / [tu – td] * R
15 km downstream in 18 min so 10 km in
(18/15)*10 = 12 min
B= 4x, R = x
Now
4x = [tu + 12] / [tu – 12] * x
Solve, tu = 20 min
Question 7 of 25
7. Question
1 points
Speed of a man in still water is 4 km/hr and the river is running at 2 km/hr. The total
time taken to go to a place and come back is 4 hours. What is the distance travelled?
A boat takes 25 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 5 km/hr and the speed of the boat in still water is 10 km/hr, what is the distance between A and B?
Correct
Downstream speed = 10+5 = 15
Upstream speed = 10-5 = 5
Now total time is 25 hours
If distance between A and B is d, then distance
BC = d/2
Now distance/speed = time, so
d/15 + (d/2)/5= 25
Solve, d = 150 km
Incorrect
Downstream speed = 10+5 = 15
Upstream speed = 10-5 = 5
Now total time is 25 hours
If distance between A and B is d, then distance
BC = d/2
Now distance/speed = time, so
d/15 + (d/2)/5= 25
Solve, d = 150 km
Question 9 of 25
9. Question
1 points
A boat goes 6 km against the current of the stream in 2 hours and goes 8 km along the
current in half hour. How long will it take to go 28.5 km in stationary water?
Correct
Speed upstream = 6/2 = 3, speed downstream = 8/(1/2) = 16
Speed of boat = 1/2(3+16) = 9.5 km/hr
So time in still water = 28.5/9.5
Incorrect
Speed upstream = 6/2 = 3, speed downstream = 8/(1/2) = 16
Speed of boat = 1/2(3+16) = 9.5 km/hr
So time in still water = 28.5/9.5
Question 10 of 25
10. Question
1 points
A man can row 48 km upstream and 56 km downstream in 12 hrs. Also, he can row
54 km upstream and 70 km downstream in 14 hrs. What is the speed of man in still water?
Correct
Let upstream speed = x km/hr, downstream
speed = y km/hr
So 48/x + 56/y = 12
And 54/x + 70/y = 14
Put 1/x = u, 1/y = v
So equations are 48u + 56v = 12 and 54u + 70v
= 14
Solve the equations, u = 1/6, v = 1/14
So upstream speed = 6 km/hr, downstream speed
= 14 km/hr
Speed of boat in still water = 1/2*(6+14)=10
Incorrect
Let upstream speed = x km/hr, downstream
speed = y km/hr
So 48/x + 56/y = 12
And 54/x + 70/y = 14
Put 1/x = u, 1/y = v
So equations are 48u + 56v = 12 and 54u + 70v
= 14
Solve the equations, u = 1/6, v = 1/14
So upstream speed = 6 km/hr, downstream speed
= 14 km/hr
Speed of boat in still water = 1/2*(6+14)=10
Question 11 of 25
11. Question
1 points
A boat takes 150 min less to travel 40 km downstream than to travel the same distance
upstream. The speed of the stream is 4 km/hr. What is the downstream speed?
Correct
Let speed of boat in still water = x km/hr
So speed upstream = x-4, and speed downstream
= x+4
Now given:
Time to travel 40 km downstream = time to
travel 40 km upstream – 150/60
So 40/(x+4) = 40/(x-4) – 5/2
8/(x-4) – 8/(x+4) = 1/2
x+4 – (x-4)/(x2 – 16) = 1/16
solve, x = 12
so downstream speed = 12+4=16
Incorrect
Let speed of boat in still water = x km/hr
So speed upstream = x-4, and speed downstream
= x+4
Now given:
Time to travel 40 km downstream = time to
travel 40 km upstream – 150/60
So 40/(x+4) = 40/(x-4) – 5/2
8/(x-4) – 8/(x+4) = 1/2
x+4 – (x-4)/(x2 – 16) = 1/16
solve, x = 12
so downstream speed = 12+4=16
Question 12 of 25
12. Question
1 points
A man rows to a place 40 km distant and back in a total of 18 hours. He finds that he
can row 5 km with the stream in the same time as 4 km against the stream. What is the
speed of boat in still water?
Correct
Suppose he moves 5km downstream in x hours
Then, downstream speed a= 5/x km/hr
Speed upstream speed b = 4/x km/hr
40 / (5 /x) + 40 / (4/x) = 18
8x + 10x = 18
x = 1
a = 5 km/hr, b = 4 km/hr
speed of boat = ½ (5 + 4 ) = 9/2 km/hr
Incorrect
Suppose he moves 5km downstream in x hours
Then, downstream speed a= 5/x km/hr
Speed upstream speed b = 4/x km/hr
40 / (5 /x) + 40 / (4/x) = 18
8x + 10x = 18
x = 1
a = 5 km/hr, b = 4 km/hr
speed of boat = ½ (5 + 4 ) = 9/2 km/hr
Question 13 of 25
13. Question
1 points
In a stream running at 2 km/hr, a motorboat goes 6 km upstream and back
again to the starting point in 2 hours. Find the speed of boat in still water.
It takes five times as long to row a distance against the stream as to row the same distance in favor of the stream. What is the ratio of the speed of the boat in still water to
that of stream?
Correct
B = [tu + td] / [tu – td] * R
So
B =[5x + x] / [5x- x] * R
So B/R = 6/4 = 3/2
Incorrect
B = [tu + td] / [tu – td] * R
So
B =[5x + x] / [5x- x] * R
So B/R = 6/4 = 3/2
Question 15 of 25
15. Question
1 points
A boat running downstream covers a distance of 32 km in 4 hrs and for covering
the same distance upstream it takes 8 hrs. What is the speed of the stream?
Correct
Downstream speed = 32/4 = 8 km/hr
Upstream speed = 32/8 = 4 km/hr
So speed of stream = 1/2*(8-4)=6
Incorrect
Downstream speed = 32/4 = 8 km/hr
Upstream speed = 32/8 = 4 km/hr
So speed of stream = 1/2*(8-4)=6
Question 16 of 25
16. Question
1 points
A man can row upstream at 10 km/hr and downstream at 16 km/hr. Find the man’s rate
in still water and the rate of current.
Correct
Incorrect
Question 17 of 25
17. Question
1 points
A boat can row at 16 km/hr in still water and the speed of river is 10 km/hr. Find the
speed of boat with the river and speed of boat against the river.
Correct
Speed with the river (downstream) = 16+10=26
Speed against the river (upstream) = 16-10=6
Incorrect
Speed with the river (downstream) = 16+10=26
Speed against the river (upstream) = 16-10=6
Question 18 of 25
18. Question
1 points
A man goes downstream 60 km and upstream 20 km, taking 4 hrs each. What is
the velocity of current?
A man rows downstream 28 km and upstream 16 km, taking 5 hrs each time.
What is the velocity of current?
Correct
Incorrect
Question 20 of 25
20. Question
1 points
A man can row 30 km upstream and 44 km downstream in 10 hrs. Also, he can row
40 km upstream and 55 km downstream in 13 hrs. Find the speed of the man in still water.
Correct
Let upstream speed = x, downstream speed = y
km/hr
Then, 30/x + 44/y = 10 and 40/x + 55/y = 13
Put 1/x = a, 1/y = b
Solve the equations.
A = 1/5, b = 1/11
So, x = 5, y = 11
Speed in still water = (5+11)/2 = 8
Incorrect
Let upstream speed = x, downstream speed = y
km/hr
Then, 30/x + 44/y = 10 and 40/x + 55/y = 13
Put 1/x = a, 1/y = b
Solve the equations.
A = 1/5, b = 1/11
So, x = 5, y = 11
Speed in still water = (5+11)/2 = 8
Question 21 of 25
21. Question
1 points
A man can row 24 km upstream and 36 km downstream in 6 hrs. Also, he can row 36 km upstream and 24 km downstream in 6.5 hrs. Find the speed of the current.
Correct
Incorrect
Question 22 of 25
22. Question
1 points
A man can row 6 km/hr in still water. When the river is running at 2 km/hr, it takes
him 1 ½ hr to row to a place and come back. How far is the place?
Correct
B is speed of boat in still water, R is speed of
stream
Time is total time taken for upstream and
downstream
Distance = time * [B^2 – R^2] / 2*B
=3/2 * [6^2 – 2^2] / 2*6
Incorrect
B is speed of boat in still water, R is speed of
stream
Time is total time taken for upstream and
downstream
Distance = time * [B^2 – R^2] / 2*B
=3/2 * [6^2 – 2^2] / 2*6
Question 23 of 25
23. Question
1 points
In a stream running at 2 km/hr, a motorboat goes 10 km upstream and back again to the starting point in 55 minutes. Find the speed (km/hr) of the motorboat in still water.
A man can row a certain distance downstream in 2 hours and return the same distance in 6 hours. If the speed of current is 22 km/hr, find the speed of man in still water.
Correct
B = [tu + td] / [tu – td] * R
B = [6+2] / [6-2] * 22
B = 44
Incorrect
B = [tu + td] / [tu – td] * R
B = [6+2] / [6-2] * 22
B = 44
Question 25 of 25
25. Question
1 points
A man can row 9 3/5 km/hr in still water and he finds that it takes him twice as much
time to row up than as to row down the same distance in river. The speed (km/hr) of the
current is
Correct
Let downstream time = t, then upstream time =
2t
B = [tu + td] / [tu – td] * R
48/5 = [2t+t] / [2t-t] * R
Incorrect
Let downstream time = t, then upstream time =
2t
B = [tu + td] / [tu – td] * R
48/5 = [2t+t] / [2t-t] * R
