M4maths Previous Puzzles

07 Jul 2020 Series

April , August , December , February, ?

OPtion

1) March
2) May
3) June
4) July
5) April
6) January
7) November
8) October
9) September
10) None of these

Solution

Months arranged in alphabetical order

Correct Option: 6 Best Solution (1)

06 Jul 2020 Age

One year ago, Smitha was four times as old as her daughter Pallavi. Six years hence, Smitha’s age will exceed her daughter’s age by 9 years. The ratio of the present ages of Smith and her daughter is:

OPtion

1) 9:2
2) 7:2
3) 13:3
4) 13:5
5) 12:5
6) 14:3
7) 13:4
8) 14:5
9) 15:5
10) None of these

Solution

Let the ages of Smitha and Pallavi 1 year ago be 4x and x years respectively.

Then, [(4x+1)+6]-[(x+1)+6]=9

=>3x=9

=> x=3

therefore, Required ratio= (4x+1):(x+1)= 13:4

Correct Option: 7 Best Solution (0)

03 Jul 2020 Simplification

There are two buildings P and Q. If 75 persons are sent from P to Q, then the number of persons in each building is the same. If 25 persons are sent from Q to P, then the number of persons in P is double the number of persons in Q. How many persons are there in building P?

OPtion

1) 450
2) 320
3) 425
4) 225
5) 335
6) 315
7) 340
8) 375
9) 350
10) None of these

Solution

Let number of persons in building P be P and
number of persons in building Q be Q

P-75 = Q+75
=> P = Q + 150 ---- (i)

P+25= 2(Q-25)
=> P + 75 = 2Q ---- (ii)

Putting value of P from (i) in (ii)
Q+ 150 + 75 = 2Q
Q = 225
P = 375

Correct Option: 8 Best Solution (0)

02 Jul 2020 Numbers

What could be the value of # in this number: 985#865, if this number is divisible by 9?

OPtion

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

Solution

If a number is divisible by 9, the sum of digits is also divisible by 9

9 + 8 + 5 + # + 8 + 6 + 5 = 9x
41 + # = 9x
Smallest value of 9x would be 45
41 + # = 45
# = 4

Correct Option: 5 Best Solution (1)

01 Jul 2020 Permutation

Using all the letters of the word GIFT how many distinct words can be formed?

OPtion

1) 64
2) 32
3) 256
4) 24
5) 128
6) 56
7) 48
8) 36
9) 12
10) None of these

Solution

4*3*2 = 24

Correct Option: 4 Best Solution (0)

30 Jun 2020 Roots

Whats is the product of sum of roots and product of roots of below quadratic equation
x² -5x + 6 = 0

OPtion

1) 5/6
2) -5/6
3) 6/5
4) -6/5
5) 6
6) 5
7) -6
8) 30
9) -30
10) None of these

Solution

x² -5x + 6 = 0
=> x²-3x-2x+6
=> x(x-3) - 2(x-3)
=> (x-2)(x-3) = 0
x = 2 oe 3

Sum of roots = 5
Product of roots = 6
Product of both = 30

Correct Option: 8 Best Solution (0)

29 Jun 2020 Simple Interest

A sum of Rs 12,500 amounts to Rs. 15,500 in the 4 years at the rate of simple interest. Find the rate percent

OPtion

1) 12
2) 8
3) 5
4) 6.5
5) 7.5
6) 6
7) 7
8) 8.5
9) 9
10) None of these

Solution

S.I.=P∗R∗T/100
=>R=(S.I.∗100)/(P∗T)


So, S.I = 15500 - 12500 = 3000.

=>R=3000∗100/(12500∗4)=6%

Correct Option: 6 Best Solution (6)

26 Jun 2020 Age

Sum of age of 9 children born at interval of 9 years is 369. What is the age of youngest child?

OPtion

1) 12
2) 8
3) 5
4) 16
5) 11
6) 15
7) 30
8) 18
9) 4
10) None of these

Solution

Let the ages of children be x, (x+9*1),
(x+9*2).... (x+7*8) years.

=> x + (x+9*1) + (x+9*2)+ (x+9*3) + (x+9*4) + (x+9*5) + (x+9*6)+ (x+9*7) + (x+9*8) = 369
=> 9x + 324 = 369
=> x = 5

Correct Option: 3 Best Solution (3)

25 Jun 2020 Arithmetic

The sum of squares of three successive integers is 20174. Sum of these integers is?

OPtion

1) 276
2) 216
3) 246
4) 266
5) 286
6) 284
7) 279
8) 281
9) 296
10) None of these

Solution

(a-1)^2 + a^2 + (a+1)^2 = 20174
=> a^2 -2a + 1 + a^2 + a^2 + 2a + 1 = 20174
=> 3a^2 + 2 = 20174
=> a^2 = (20174-2)/3 = 6724
=> a = 82
So the 3 numbers are 81, 82 and 83 and their sum is 246

Correct Option: 3 Best Solution (0)

24 Jun 2020 Series

Given the series:
4, 7, 12, 21, 38, ..
What is sum of seventh and ninth term?

OPtion

1) 810
2) 658
3) 626
4) 536
5) 696
6) 691
7) 698
8) 502
9) 582
10) None of these

Solution

Series is formed by adding 2^n+1 in previous number
So
4 + 2^1+1 = 7
7 + 2^2+1 = 12
12 + 2^3+1 = 21
21 + 2^4+1 = 38
38 + 2^5+1 = 71
71 + 2^6+1 = 136
136 + 2^7+1 = 265
265 + 2^8+1 = 522

Sum of 522 + 136 = 658

Correct Option: 2 Best Solution (0)