Basic Maths Mcqs - Set 7

1)   A man swims downstream 30 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?

a. 2 kmph
b. 8 kmph
c. 16 kmph
d. 4 kmph
Answer  Explanation 

ANSWER: 8 kmph

Explanation:
30 — 3 DS = 10
? —- 1
18 —- 3 US = 6
? —- 1 M = ?

M = (10 + 6)/2 = 8


2)   A boat can move upstream at 25 kmph and downstream at 35 kmph, then the speed of the current is_________?

a. 5 kmph
b. 10 kmph
c. 30 kmph
d. 15 kmph
Answer  Explanation 

ANSWER: 5 kmph

Explanation:
US = 25
DS = 35
M = (35 – 25)/2 = 5


3)   A man can row upstream at 25 kmph and downstream at 35 kmph, and then find the speed of the man in still water?

a. 60 kmph
b. 10 kmph
c. 30 kmph
d. 5 kmph
Answer  Explanation 

ANSWER: 30 kmph

Explanation:
US = 25
DS = 35
M = (35 + 25)/2 = 30


4)   A man can row with a speed of 15 kmph in still water. If the stream flows at 5 kmph, then the speed in downstream is________?

a. 10 kmph
b. 5 kmph
c. 20 kmph
d. 22 kmph
Answer  Explanation 

ANSWER: 20 kmph

Explanation:
M = 15
S = 5
DS = 15 + 5 = 20


5)   A man can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is_________?

a. 3
b. 7.5
c. 2.25
d. 1.5
Answer  Explanation 

ANSWER: 1.5

Explanation:
M = 4.5
S = x
DS = 4.5 + x
US = 4.5 + x
4.5 + x = (4.5 – x)2
4.5 + x = 9 -2x
3x = 4.5
x = 1.5


6)   A man can row his boat with the stream at 6 km/h and against the stream in 4 km/h. The man’s rate is________?

a. 1 kmph
b. 5 kmph
c. 8 kmph
d. 3 kmph
Answer  Explanation 

ANSWER: 1 kmph

Explanation:
DS = 6
US = 4
S = ?
S = (6 – 4)/2 = 1 kmph


7)   A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is________?

a. 7 km/h
b. 5 km/h
c. 3 km/h
d. 2 (1/2) km/h
Answer  Explanation 

ANSWER: 2 (1/2) km/h

Explanation:
100 — 10 DS = 10
? —- 1
75 —- 15 US = 5
? —– 1 S = (10 – 5)/2

= 2 2 ½ kmph


8)   A person can swim in still water at 4 km/h. If the speed of water 2 km/h, how many hours will the man take to swim back against the current for 6km?

a. 3
b. 4
c. 4 (1/2)
d. Insufficient data
Answer  Explanation 

ANSWER: 3

Explanation:
M = 4
S = 2
US = 4 – 2 = 2
D = 6
T = 6/2 = 3


9)   If a man rows at the rate of 5 kmph in still water and his rate against the current is 3.5 kmph. then the man’s rate along the current is__________?

a. 4.25 kmph
b. 6 kmph
c. 6.5 kmph
d. 8.5 kmph
Answer  Explanation 

ANSWER: 6.5 kmph

Explanation:
No explanation is available for this question!


10)   A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is________?

a. 2 : 1
b. 3 : 1
c. 3 : 2
d. 4 : 3
Answer  Explanation 

ANSWER: 3 : 1

Explanation:
No explanation is available for this question!


11)   Speed of a boat in standing water is 9 kmph and the speed of the stream is 1.5 kmph. A man rows to a place at a distance of 105 km and comes back to the starting point. The total time taken by him is_________?

a. 16 hours
b. 18 hours
c. 20 hours
d. 24 hours
Answer  Explanation 

ANSWER: 24 hours

Explanation:
No explanation is available for this question!


12)   A man can row three-quarters of a kilometre against the stream in 11 minutes and down the stream in 7 minutes. The speed (in km/hr) of the man in still water is:_________?

a. 2
b. 3
c. 4
d. 5
Answer  Explanation 

ANSWER: 5

Explanation:
No explanation is available for this question!


13)   A boatman goes 2 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 5 km in stationary water?

a. 40 minutes
b. 1 hour
c. 1 hr 15 min
d. 1 hr 30 min
Answer  Explanation 

ANSWER: 1 hr 15 min

Explanation:
No explanation is available for this question!


14)   A man can row 9 1/3 km/hr in still water and he finds that is thrice as much time to row u p than as to row down the same distance in river. The speed of the current is:________?

a. 3 1/3 km/hr
b. 3 1/9 km/hr
c. 1 ¼ km/hr
d. 4 2/3 km/hr
Answer  Explanation 

ANSWER: 4 2/3 km/hr

Explanation:
Let Speed upstream = x km/hr

Speed downstream = 3x km/hr

Speed in still water = ½ (x+3x) km/hr = 2x km/hr

Speed of current = ½ (3x-x) km/hr = x km/hr

2x = 28/3 or x = 14/3 = 4 2/3 km/hr


15)   A boat travels upstream from B to A and downstream from A to B in 3 hours. If the speed of the boat in still water is 9km/hr and the speed of the current is 3km/hr, the distance A and B is:_______?

a. 4km
b. 6 km
c. 8 km
d. 12 km
Answer  Explanation 

ANSWER: 12 km

Explanation:
Speed downstream = (9+3) km/hr = 12km/hr

Speed upstream = (9-3) km/hr = 6 km/hr

Distance AB = x km

x/6 + x/12 = 3

=> 2x + x = 36

=> x= 12


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

a. 1.5km/hr
b. 3km/hr
c. 1km/hr
d. none
Answer  Explanation 

ANSWER: 1km/hr

Explanation:
Let the speed of stream be x km/hr

Speed upstream = (2-x) km/hr = 2-x = 1 => x = 1 km/hr


17)   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?

a. 1 : 2
b. 3 : 1
c. 2 : 1
d. 1 : 3
Answer  Explanation 

ANSWER: 3 : 1

Explanation:
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


18)   A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will he take to go 5km in stationery water?

a. 40 Minutes
b. 1 Hour
c. 1 hr 15 Min
d. 1 Hr 30 Min
Answer  Explanation 

ANSWER: 1 hr 15 Min

Explanation:
Speed upstream = 2km/hr.

Speed downstream = 6 km/hr

Speed in stationary water = ½ (6 + 2) km/hr = 4 km/hr

Time is taken to cover 5 km in stationary water

= (1/4 x 5) 1 hr 15 min


19)   The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg. Find the average weights of all the boys in the class.

a. 47.55 kg
b. 48 kg
c. 48.55 kg
d. 49.25 kg
Answer  Explanation 

ANSWER: 48.55 kg

Explanation:
No explanation is available for this question!


20)   If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is__________?

a. 53.33
b. 54.68
c. 55
d. None of these
Answer  Explanation 

ANSWER: 54.68

Explanation:
Required average = (55 x 50 + 60 x 55 + 45 x 60) / (55 + 60 + 45)
= (2750 + 3300 + 2700) /160
= 54.68 is correct Answer