Basic Maths Mcqs - Set 6

1)   The speed of a boat in still water is 5 km/hr, it can go 30km upstream and return downstream to the original point in 4 hours 30 min. The speed of the stream is_______?

a. 5km/hr
b. 8 km/hr
c. 10 km/hr
d. 15 km/hr
Answer  Explanation 

ANSWER: 5km/hr

Explanation:
No explanation is available for this question!


2)   A boat covers a distance of 30 km in 2 ½ hours running downstream while returning it covers the same distance in 3 ¾ hours. What is the speed of the boat in still water?

a. 8km/hr
b. 12km/hr
c. 14 km/hr
d. 15 km/hr
e. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Speed downstream = (30 x 2/5)km/hr = 12km/hr
Speed upstream = (30 x 4/15) km/hr = 8 km/hr
Speed of boat in still water = ½ (12 + 8)km/hr = 10 km/hr


3)   A boat goes 24 km downstream in 10 hours, it takes 2 hours more to cover the same distance against the stream. What is the speed of the boat in still water?

a. 2km/hr
b. 2.8 km/hr
c. 4 km/hr
d. 4.2 km/hr
e. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Speed downstream = 24/10 km/hr = 2.4 km/hr
Speed upstream = 24/12 km/hr = 2 km/hr
Speed of the boat in still water = ½ (2.4 +2)km/hr = 2.2 km/hr


4)   A boat running downstream covers 24 km’s in 4 hours while for covering the same distance upstream it takes 6 hours whats the speed of the boat in still water?

a. 3.5km/hr
b. 5.5 km/hr
c. 6 km/hr
d. Data Inadequate
e. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Speed downstream = 24/4 km/hr = 6 km/hr
Speed upstream = 24/6 km/hr = 4 km/hr
Speed of the boat in still water = ½ (6 +4)km/hr = 5 km/hr


5)   A person can row at 9 kmph and still water. He takes 4 1/2 hours to row from A to B and back. What is the distance between A and B if the speed of the stream is 1 kmph?

a. 32 km
b. 25 km
c. 28 km
d. 24 km
e. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
Let the distance between A and B be x km.

Total time = x/(9 + 1) + x/(9 – 1) = 4.5
=> x/10 + x/8 = 9/2 => (4x + 5x)/40 = 9/2 => x = 20 km.


6)   The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 60 metres?

a. 10 seconds
b. 15 seconds
c. 20 seconds
d. 12 seconds
e. None of these
Answer  Explanation 

ANSWER: 12 seconds

Explanation:
Speed of the boat downstream = 15 + 3 = 18 kmph

= 18 * 5/18 = 5 m/s
Hence time taken to cover 60 m = 60/5 = 12 seconds.


7)   A boat is rowed downstream at 15.5km/hr and upstream at 8.5 km/hr. The speed of the stream is________?

a. 3.5km/hr
b. 5.75km/hr
c. 6.5km/hr
d. 7km/hr
Answer  Explanation 

ANSWER: 3.5km/hr

Explanation:
Speed Downstream = 15.5 km/hr,
speed upstream = 8.5 km/hr
Speed of the stream = ½ (15.5 – 8.5)km = 3.5 km/hr


8)   A man can row downstream at 18 kmph and upstream at 10 kmph. Find the speed of the man in still water and the speed of stream respectively?

a. 13, 3
b. 12, 6
c. 15, 3
d. 14, 4
Answer  Explanation 

ANSWER: 14, 4

Explanation:
Let the speed of the man in still water and speed of stream be x kmph and y kmph respectively.

Given x + y = 18 — (1)
and x – y = 10 — (2)
From (1) & (2) 2x = 28 => x = 14, y = 4.


9)   A man can row 30 km downstream and 20 km upstream in 4 hours. He can row 45 km downstream and 40 km upstream in 7 hours. Find the speed of man in still water?

a. 15 kmph
b. 10 kmph
c. 12 kmph
d. 12.5 kmph
e. None of these
Answer  Explanation 

ANSWER: 12.5 kmph

Explanation:
Let the speed of the man in still water be a kmph and let the speed of the stream be b kmph.

Now 30/(a + b) + 20/(a – b) = 4 and 45/(a + b) + 40/(a – b) = 7
Solving the equation, the speed of man in still water is 12.5 kmph.


10)   The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

a. 12 kmph
b. 13 kmph
c. 14 kmph
d. 15 kmph
Answer  Explanation 

ANSWER: 14 kmph

Explanation:
The ratio of the times taken is 2:1.
The ratio of the speed of the boat in still water to the speed of the stream = (2+1)/(2-1) = 3/1 = 3:1
Speed of the stream = 42/3 = 14 kmph.


11)   A man can row a boat at 20 kmph in still water. If the speed of the stream is 6 kmph, what is the time taken to row a distance of 60 km downstream?

a. 20/6 hours
b. 27/2 hours
c. 30 hours
d. 30/13 hours
Answer  Explanation 

ANSWER: 30/13 hours

Explanation:
Speed downstream = 20 + 6 = 26 kmph.
Time required to cover 60 km downstream = d/s = 60/26 = 30/13 hours.


12)   A man rows his boat 85 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?

a. 5 kmph
b. 6 kmph
c. 7 kmph
d. 8 kmph
Answer  Explanation 

ANSWER: 8 kmph

Explanation:
Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 – 18)/2 = 8 kmph


13)   The speed of a boat in upstream is 60 kmph and the speed of the boat downstream is 80 kmph. Find the speed of the boat in still water and the speed of the stream?

a. 70, 10 kmph
b. 35, 27 kmph
c. 50, 60 kmph
d. 45, 55 kmph
Answer  Explanation 

ANSWER: 70, 10 kmph

Explanation:
Speed of the boat in still water = (60+80)/2 = 70 kmph. Speed of the stream = (80-60)/2 = 10 kmph.


14)   The speed of a boat in still water is 60kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?

a. 35, 25 kmph
b. 80, 40 kmph
c. 40, 60 kmph
d. 50, 55 kmph
Answer  Explanation 

ANSWER: 80, 40 kmph

Explanation:
Speed downstream = 60 + 20 = 80 kmph
Speed upstream = 60 – 20 = 40 kmph


15)   The current of a stream at 1 kmph. A motor boat goes 35 km upstream and back to the starting point in 12 hours. The speed of the motor boat in still water is_________?

a. 6 kmph
b. 7 kmph
c. 8.5 kmph
d. 8 kmph
Answer  Explanation 

ANSWER: 6 kmph

Explanation:
S = 1
M = x
DS = x + 1
US = x – 1
35/(x + 1) + 35/(x – 1) = 12
x = 6


16)   A man whose speed is 4.5 kmph in still water rows to a certain upstream point and back to the starting point in a river which flows at 1.5 kmph, find his average speed for the total journey?

a. 8 kmph
b. 4 kmph
c. 2 kmph
d. 10 kmph
Answer  Explanation 

ANSWER: 4 kmph

Explanation:
M = 45
S = 1.5
DS = 6
US = 3
AS = (2 * 6 * 3) /9 = 4


17)   The current of a stream runs at the rate of 4 kmph. A boat goes 6 km and back to the starting point in 2 hours, then find the speed of the boat in still water?

a. 10 kmph
b. 21 kmph
c. 8 kmph
d. 12 kmph
Answer  Explanation 

ANSWER: 8 kmph

Explanation:
S = 4
M = x
DS = x + 4
US = x – 4
6/(x + 4) + 6/(x – 4) = 2
x = 8


18)   A man can row 6 kmph in still water. When the river is running at 1.2 kmph, it takes him 1 hour to row to a place and black. What is the total distance traveled by the man?

a. 6.24 km
b. 6 km
c. 5.76 km
d. 5.66 km
Answer  Explanation 

ANSWER: 5.76 km

Explanation:
M = 6
S = 1.2
DS = 7.2
US = 4.8
x/7.2 + x/4.8 = 1
x = 2.88
D = 2.88 * 2 = 5.76


19)   A man can row 6 kmph in still water. When the river is running at 1.2 kmph, it takes him 1 hour to row to a place and black. How far is the place?

a. 3.12 km
b. 2.88 km
c. 3 km
d. 2 km
Answer  Explanation 

ANSWER: 2.88 km

Explanation:
M = 6
S = 1.2
DS = 6 + 1.2 = 7.2
US = 6 – 1.2 = 4.8
x/7.2 + x/4.8 = 1
x = 2.88


20)   A man swims downstream 72 km and upstream 45 km taking 9 hours each time; what is the speed of the current?

a. 3 kmph
b. 1.5 kmph
c. 13 kmph
d. 6.5 kmph
Answer  Explanation 

ANSWER: 1.5 kmph

Explanation:
72 — 9 DS = 8
? —- 1
45 —- 9 US = 5
? —- 1 S = ?
S = (8 – 5)/2 = 1.5