M4maths Previous Puzzles

26 May 2021 Percentage

A student got 90 % marks in an exam of 500 marks. If marks of Physics are printed 94 instead of 72, then the true % obtained by the student will be

OPtion

1) 89%
2) 88%
3) 94%
4) 92%
5) 87%
6) 80%
7) 86%
8) 83%
9) 85%
10) None of the above

Solution

total difference of marks = 94-74 = 20
5 marks = 1% (total marks = 500 so 1 % = 500/100 = 5 marks)
20/5 = 4% so true % = 90-4 = 86%

Correct Option: 7 Best Solution (0)

25 May 2021 BOATS AND STREAMS

The velocity of a river is 2 km/hour. How much time is required to travel a boat in that river for 10 km. downstream then 10 km. upstream. Velocity of boat is 3km./hour in still water.

OPtion

1) 3 hrs
2) 4 hrs
3) 5 hrs
4) 6 hrs
5) 8 hrs
6) 12 hrs
7) 14 hrs
8) 15 hrs
9) 16 hrs
10) none of these

Solution

net velocity downstream = 3+2 = 5 km./hrs.
net velocity upstream = 3-2 = 1 km./hrs.
so total time required = (10/5) + (10/1)
= 2 + 10 = 12 hrs.

Correct Option: 6 Best Solution (3)

24 May 2021 PROBABILITY

5 pairs of two ball (1 white 1 red) are available. We have to select 1 white and 1 red ball. Probability to select both the balls of same pair will be?

OPtion

1) 1/2
2) 2/3
3) 3/4
4) 1/4
5) 2/5
6) 1/5
7) 2/7
8) 1/9
9) 3/10
10) none of these

Solution

Any of the ball can be selected in 1st attempt.
In second attempt we have to select a ball from the same pair.
Its probability will be 1/5

Correct Option: 6 Best Solution (2)

21 May 2021 Rate

The cost of 3 types of wheat are 10-rupee, 14 rupee and 16 rupees. What will be the rate of a mixture of 20 Kg, 50 Kg and 40 Kg wheat of these 3 types respectively.

OPtion

1) 10
2) 11
3) 14
4) 13
5) 12
6) 15
7) 16
8) 17
9) 18
10) none of these

Solution

Rate of 20kg of 10rs wheat = 20*10 = 200rs
Rate of 5okg of 14rs wheat = 50*14 = 700rs
Rate of 40kg of 16rs wheat = 40*16 = 640rs
Mixture of all the three= Total rupees/Total kg's
= 200+700+340/20+50+40
= 1540/110
= 14rs per kg.

Correct Option: 3 Best Solution (0)

20 May 2021 sequence

What will be the next number of the following sequence?
0, 3, 22, 93, ..........

OPtion

1) 134
2) 167
3) 190
4) 201
5) 234
6) 276
7) 297
8) 304
9) 404
10) none of these

Solution

0, 3, 22, 93, ..........
0+0^2+0^4 =0
1+1^2+1^4=3
2+2^2+2^4 =2+4+16=22
3^1+3^2+3^4= 3+9+81=93
4^1+4^2+4^4=4+16+256 =276

Correct Option: 6 Best Solution (0)

19 May 2021 Relation

m % of 60 = 75 % of n, relation between m and n will be?

OPtion

1) m = n
2) 1m = 2n
3) 2m = 1n
4) 9m = 8n
5) 4m = 5n
6) 3m = 5n
7) 6m = 5n
8) 5m = 4n
9) 2m = 5n
10) None of these

Solution

60m/100 = 75n/100
or 4m = 5n

Correct Option: 5 Best Solution (0)

18 May 2021 Revolutions of wheel

A wheel has a diameter of 154 cm. How many revolutions of the wheel are needed to cover a distance of 227.48 m?

OPtion

1) 26.5
2) 25.5
3) 24.5
4) 35.5
5) 55.0
6) 34.5
7) 47.0
8) 50.5
9) 55.5
10) None of these

Solution

Circumference of wheel = 2piR = 154 x 22/7 = 484 cm
Distance = 227.48 m
= 22748 cm
Revolutions = 22748/484 = 47

Correct Option: 7 Best Solution (0)

17 May 2021 PROBABILITY

An alphabet is randomly selected from the word INDIA. What is the probability that it would be I?

OPtion

1) 1/3
2) 1/6
3) 1/5
4) 2/5
5) 3/5
6) 1/2
7) 2/3
8) 4/5
9) 5/6
10) None of these

Solution

Total alphabets = 5
Number of I’s = 2
Probability = 2/5

Correct Option: 4 Best Solution (3)

14 May 2021 Discount

What will be the percentage of profit, if a shopkeeper provides a discount of 25 % after increasing the price of an object by 50 %?

OPtion

1) 25
2) 15
3) 22.5
4) 12.5
5) 32.5
6) 40
7) 50
8) 45
9) 42.5
10) None of the above

Solution

Let the original price of the object is 100
After increasing the price of object by 50 %, selling price is 150
After taking a discount of 25 % on the selling price,
Price of the object for the customer is 150 * 0.75 = 112.5
Profit percentage = 112.5/100 = 12.5

Correct Option: 4 Best Solution (2)

13 May 2021 Methods

Number of methods of distributing 6 responsibilities among 3 people is

OPtion

1) 15
2) 21
3) 12
4) 24
5) 30
6) 36
7) 56
8) 42
9) 28
10) None of the above

Solution

Formula for solving problem = (n+r-1) (n+r-2)/(r-1) (r-2)
Here n= 6 & r =3
On applying values we get (6+3-1) (6+3-2) / (3-1) (3-2) = 8*7/2*1 = 56/2 = 28

Correct Option: 9 Best Solution (0)