M4maths Previous Puzzles

04 Nov 2021 cost price

Manoj sells a machine for 65 thousand at a loss. Had he sold it for 80 thousand, his gain would have been 5 times the former loss. Find the cost price of the machine

OPtion

1. 70
2. 72
3. 65.8
4. 69.5
5. 68
6. 67.5
7. 72.6
8. 73.6
9. 77.5
10. None of the above

Solution

Manoj sells a machine for Rs 65 thousand at a loss.
Let the cost price be c.p
Loss = c.p - 65
Now, had he sold it for Rs 80 thousand, his gain would have been 5 times the former loss.
Thus, 80 - c.p = 5 (c.p - 65)
⇒ 6c.p = 405
⇒ c.p = 67.5 Lakhs

Correct Option: 6 Best Solution (2)

03 Nov 2021 Average

Find the average of squares of consecutive odd numbers from 1 to 31.

OPtion

1. 245
2. 314
3. 355
4. 366
5. 341
6. 326
7. 402
8. 385
9. 399
10. None of the above

Solution

The required average = n (n + 2) / 3
= 31 ( 31 + 2 ) 3
= 31 x 33 / 3
= 341.

Correct Option: 5 Best Solution (2)

02 Nov 2021 Simplification

Simplify the below equation: -
2.45 × 2.45 - 0.9 × 2.45 + 0.45 × 0.45

OPtion

1. 1
2. 3
3. 4
4. 2
5. 2.5
6. 2.4
7. 1.4
8. 1.6
9. 1.5
10. None of the above

Solution

Given expression
= 2.45 × 2.45 - 2 × 2.45 × 0.45 + 0.45 × 0.45
= (2.45)^2 - 2 × 2.45 × 0.45 + (0.45)^2
= (2.45 - 0.45)^2 [ a^2 - 2ab + b^2 = (a - b)^2 ]
= (2)^2 = 4.

Correct Option: 3 Best Solution (4)

01 Nov 2021 Distance

Nikhil goes to station at the speed of 6 Km/h and returns with a speed of 4 Km/h. If he takes 6 hours in all, find out the distance in Km between the village and the station.

OPtion

1. 6
2. 8
3. 8.4
4. 14.4
5. 12.5
6. 13
7. 13.5
8. 14
9. 10
10. None of the above

Solution

Here, S1 = 6, S2 = 4 and T = 6.
∴ The distance between the village and the station
= T (S1 S2/S1 + S2) = 6 {(6 X 4)/ (6 + 4)}
= 144 / 10
= 14.4 Km.

Correct Option: 4 Best Solution (4)

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)