M4maths Previous Puzzles

31 Jan 2020 Root

A man sold 12 eggs for 6 and gained 20%. How many eggs did he buy for 10 ?

OPtion

1) 22
2) 21
3) 23
4) 16
5) 18
6) 24
7) 20
8) 26
9) 28
10) None of these

Solution

Let CP be x

SP =CP + profit

6 = x + 20% of x

6 = x + (1/5)x
6 = 6x/5

x=5

In 5 he buy = 12 eggs

In Rs 10 he buy=(12/5)*10 = 24 eggs

Correct Option: 6 Best Solution (3)

30 Jan 2020 Profit and Loss

Trader marks his goods 60% above the cost price and gives a discount of 20% on the marked price. Find his gain percent.

OPtion

1) 22
2) 22.5
3) 32
4) 32.5
5) 28
6) 29.5
7) 26
8) 26.5
9) 30
10) None of these

Solution

Let the CP be 100
MRP = 160
Discounted price = 0.8*160 = 128

Profit = 128-100 = 28
Profit % = 28%

Correct Option: 5 Best Solution (0)

29 Jan 2020 Root

X and Y are the two consecutive whole numbers between which (2,400)^0.5 lies. What is the sum of x and Y?

OPtion

1) 91
2) 92
3) 93
4) 97
5) 95
6) 96
7) 98
8) 99
9) 100
10) None of these

Solution

(2,400)^0.5 = 48.99
So X and Y are 48 and 49
X+Y = 97

Correct Option: 4 Best Solution (0)

28 Jan 2020 Remainder

When a number is divided by 125, the remainder is 92, when the same number is divided by 25, the remainder will be ____.

OPtion

1) 7
2) 9
3) 11
4) 13
5) 5
6) 3
7) 17
8) 19
9) 18
10) None of these

Solution

Let the number be x
So x= 125 *K + 92
When K = 1, x = 217

271/25 = > Remainder 17

Correct Option: 7 Best Solution (3)

27 Jan 2020 RANK

Rank of the word REPUBLIC in the dictionary of words formed by the letters of the word REPUBLIC ?

OPtion

1) 32261
2) 32262
3) 32259
4) 32254
5) 32246
6) 32253
7) 32255
8) 32257
9) 32260
10) None of these

Solution

6*7! + 2*6! + 4*5! + 4*4! + 0*3! + 2*2! + 1*1! + 0*0!

30240 + 1440 + 480 + 96 + 0 + 4 + 1 + 0 = 32261
32261 + 1 = 32262
i.e., Rank of the word 'REPUBLIC' = 32262

Correct Option: 2 Best Solution (1)

24 Jan 2020 Ratio

Isha’s grandfather was 4 times older to her 3 years ago. He would be two times of her age 25 years from now. 9 years ago, what was the ratio of Isha’s age to that of her grandfather’s age?

OPtion

1) 2:51
2) 1:6
3) 2:12
4) 4:25
5) 1:3
6) 5:23
7) 3:19
8) 1:7
9) 5:18
10) None of these

Solution

Suppose Isha's grandfathers age is x and Isha's age is y

3 years ago
x-3 = 4*(y-3)
=> x = 4y - 9 --(i)

25 years from now
x+25 = 2*(y+25)
=> x = 2y + 25 --(ii)

(i) = (ii)
4y - 9 = 2y + 25
=> 2y = 34
=> y = 17
and x = 59

9 years ago
Age of Grandfather = 59 - 9 = 50
Age of Isha = 17 - 9 = 8
Ratio of ages = 8:50 = 4 : 25


Option 4)

Correct Option: 4 Best Solution (0)

23 Jan 2020 Probability

What is the average of the seventh even number, fifth and eleventh odd number after 400?

OPtion

1) 408
2) 412
3) 410
4) 414
5) 415
6) 416
7) 413
8) 417
9) 418
10) None of these

Solution

Numbers are
7th Even number = 414
5th odd number = 409
11th odd number = 421

Average = 414.667

Correct Option: 10 Best Solution (0)

22 Jan 2020 Arithmetic

The sum of squares of three successive integers is 6629. Sum of these integers is?

OPtion

1) 121
2) 122
3) 123
4) 131
5) 113
6) 103
7) 102
8) 101
9) 141
10) None of these

Solution

(a-1)^2 + a^2 + (a+1)^2 = 6629
=> a^2 -2a + 1 + a^2 + a^2 + 2a + 1 = 6629
=> 3a^2 + 2 = 6629
=> a^2 = (20174-2)/3 = 2209
=> a = 47
So the 3 numbers are 46, 47 and 48 and their sum is 141

Correct Option: 9 Best Solution (4)

21 Jan 2020 Volume

143.4 cubic centimeters of silver is drawn into a wire 2 mm in diameter. The length if the wire will be:

OPtion

1) 45.5cm
2) 45cm
3) 45mm
4) 4500m
5) 45000cm
6) 45500mm
7) 45m
8) 0.45mm
9) 450m
10) None of these

Solution

Let the length of the wire be h
Radius=2/2 mm = 1/10 cm
Volume = πr^2h= 143.4
=> (22/7)∗(1/10)∗(1/10)∗h = 143.4
=>h = (143.4∗10∗10∗7)/22 = 4562cm = 45.63m = 45620mm

Correct Option: 10 Best Solution (0)

20 Jan 2020 Probability

Students at a local college were asked how many hours they slept last night. The given values below shows the data. Find the probability that a randomly picked student slept for 6 hours?

Sleep Hours Count of Students
6 14
7 26
8 28
9 15
More than 10 8

OPtion

1) 2/13
2) 14/89
3) 14/87
4) 14/93
5) 14/90
6) 14/92
7) 2/17
8) 2/15
9) 14/83
10) None of these

Solution

Total number of students = 91
Total number of students who slept for 6 hours = 14

Probability = 14/91 = 2/13

Correct Option: 1 Best Solution (0)