M4maths Previous Puzzles

29 Oct 2021 Selling

On selling 14 T-shirts at 7640, there is a loss equal to the cost price of 6 T-shirts. The cost price of a T-shirt is?

OPtion

1. 610
2. 855
3. 825
4. 950
5. 1050
6. 955
7. 735
8. 750
9. 1000
10. None of the above

Solution

Let, the C.P. of a T-shirts be x.
∴ S.P. of 13 T-shirt = 7640
Now, according to the question,
=> 14x - 7640 = 6x
=> 8x = 7640
X = 7640/8
X = 955

Correct Option: 6 Best Solution (3)

28 Oct 2021 AVERAGE

The average of 12 numbers is 8. If the average of first 11 of these numbers is 7, the twelfth number is:

OPtion

1. 22
2. 26
3. 12
4. 15
5. 17
6. 20
7. 18
8. 19
9. 16
10. None of the above

Solution

Sum of seven numbers = 12 × 8 = 96
Sum of first six numbers = 11 × 6 = 77
Therefore, the seventh number = 96 − 77 = 19

Correct Option: 8 Best Solution (3)

27 Oct 2021 AVERAGE

The average of x numbers is 5x. If x − 2 is subtracted from each given number, what will be the new average?

OPtion

1. 2x + 2
2. 5x + 2
3. 4x + 3
4. 4x + 1
5. 4x + 2
6. 5x + 1
7. 3x + 2
8. 3x + 1
9. 7x + 2
10. None of the above

Solution

The new average = x − a = 5x − (x − 2)
= 4x + 2

Correct Option: 5 Best Solution (0)

26 Oct 2021 Relation

k % of 90 = 80 % of y
relation between k and y will be

OPtion

1) k=y
2) 3k=2y
3) 3k=8y
4) 9k=4y
5) 9k=8y
6) 8k=9y
7) 9k=10y
8) 10k=9y
9) 2k=9y
10) none of these

Solution

90k/100 = 80y/100
or 9k = 8y

Correct Option: 5 Best Solution (3)

25 Oct 2021 sequence

next number of the following sequence 28, 57, 116, 235, 474 will be

OPtion

2) 590
3) 675
4) 744
5) 505
6) 645
7) 953
8) 499
9) 605
10) none of these

Solution

(28*2)+1=57
(57*2)+2=116
(116*2)+3=235
(235*2)+4=474

(474*2)+5=953

Correct Option: 7 Best Solution (4)

22 Oct 2021 AVERAGE

The average of first set of 6 numbers is 14, second set of 8 numbers is 12 and third set of 14 numbers is 18. Calculate the average of all the numbers

OPtion

1) 10.95
2) 10.99
3) 15.42
4) 11.57
5) 12.23
6) 12.89
7) 13.45
8) 13.95
9) 14.78
10) none of these

Solution

sum of first set 6 numbers is 14*6 = 84

sum of second set 8 numbers is 12*8 = 96

sum of third set 14 numbers is 14*18 = 252

total sum of 28 numbers is =(84+96+252) = 432

Average of 28 numbers is = 432/28 = 15.42

Correct Option: 3 Best Solution (5)

21 Oct 2021 Study

In a college, 25% of the student’s study Hindi and English. 45% of the student’s study English. What is the probability of a student studying Hindi given he/she is already studying English?

OPtion

1. 0.675
2. 0.580
3. 0.875
4. 0.725
5. 0.555
6. 0.445
7. 0.465
8. 0.665
9. 0.659
10. None of the above

Solution

P(T and E) = 0.25
P(E) = 0.45
P(T/E) = P(T and E)/P(E) = 0.25/0.45
= 0.555

Correct Option: 5 Best Solution (2)

20 Oct 2021 arrangement

There are 8 A-type, 2 B-Type and 4 C-type objects are in a bag. All the 14 objects are drawn one by one and arranged in a row. Find out the number of different arrangements possible.

OPtion

1. 40240
2. 50250
3. 50050
4. 55055
5. 62025
6. 66046
7. 45045
8. 48056
9. 42016
10. None of the above

Solution

Number of different arrangements possible = {14!} / {8! 2! 4!}
= {14×13×12×11×10×9×8×7×6×5×4×3×2 } / {(8×7×6×5×4×3×2 ) (2) (4×3×2)}}
= {14×13×12×11x10x9} / {(2)(4×3×2)} = {7×13×3×11x5×3} = 45045

Correct Option: 7 Best Solution (4)

18 Oct 2021 share

The cost of a share is decreased by 20%. If the original cost is $120, find the decrease cost.

OPtion

1. 110
2. 100
3. 102
4. 104
5. 98
6. 95
7. 96
8. 108
9. 90
10. None of the above

Solution

Original cost = $120
Decrease in it = 20% of $120 = 20/100 × 120
= 2400/100 = $24
Therefore, decrease cost = $120 - $24 = $96

Correct Option: 7 Best Solution (2)

15 Oct 2021 Rectangle

The length of a rectangle doormat is twice its breadth. If its length is decreased by 15cm and breadth is increased by 15 cm, the area of the rectangle is increased by 275sq. cm. Find the length of the rectangle.

OPtion

1. 33.33
2. 80
3. 40
4. 60.50
5. 66.66
6. 65.30
7. 60
8. 50.50
9. 55.55
10. None of the above

Solution

Let breadth = x.
Then, length = 2x
Then, (2x -15) (x + 15) - 2x * x = 275
30x – 15x- 225= 275
15x = 500
x = 33.33
Length of the rectangle = 2x = 66.66 cm.

Correct Option: 5 Best Solution (2)