M4maths Previous Puzzles

01 Nov 2019 Simple Interest

A sum of money at simple interest amounts to Rs. 690 in 3 years and to Rs. 720 in 4 years. The sum is:

OPtion

1) 750
2) 650
3) 640
4) 550
5) 500
6) 700
7) 600
8) 625
9) 450
10) None of these

Solution

S.I. for 1 year = Rs. (720 - 690) = Rs. 30.

S.I. for 3 years = Rs.(30 x 3) = Rs. 90.

Principal = Rs. (690 - 90) = Rs. 600.

Correct Option: 7 Best Solution (5)

31 Oct 2019 Age

Mr. Tanpura says to his son Guitar: " My age was two years more than 7 times of yours age before
25 & 1/2 years and after 7 & 1/2 a year, my age will be twice of yours age of 1/2 a year before".
What will be the age of Guitar after 10 and 1/2 a year.

OPtion

1) 43
2) 42
3) 41
4) 40
5) 48
6) 39
7) 50
8) 38
9) 28.5
10) None of these

Solution

Let the age of tanpura be x and guitar be y.
We get following equations from given conditions:
x - 25.5 = 7 (y - 25.5) + 2
x + 7.5 = 2(y - 0.5)

Solving we get y = 28.5
After 10.5 years, age of y = 39

Correct Option: 6 Best Solution (0)

30 Oct 2019 Area

If the diagonal of a rectangle is 47cm long and its perimeter is 96 cm. Find the area of the rectangle in sq. cm.

OPtion

1) 95
2) 48.5
3) 47.5
4) 94
5) 49.5
6) 93
7) 46.5
8) 92
9) 45.5
10) None of these

Solution

Let length = x and breadth = y then

2(x+y) = 96 => x+y = 48
x²+y² = 47² = 2209
now (x+y)² = 39² = 2304
=> x²+y²+2xy= 2304
=> 2209 + 2xy = 2304
=> xy = 47.5
area = xy = 47.5 sq.cm

Option 3)

Correct Option: 3 Best Solution (0)

29 Oct 2019 Even Number

How many factors of 42996970800 are even numbers?

OPtion

1) 750
2) 800
3) 640
4) 960
5) 580
6) 150
7) 125
8) 648
9) 240
10) None of these

Solution

42996970800 = 53^1 * 73^1 * 7^3 * 5^2 * 2^4 * 3^4

Any factor of this number should be of the form 53^a * 73^b * 7^c * 5^d * 2^e * 3^f.

For the factor to be an even number e should be non zero.

a can take values 0, 1
b can take values 0, 1
c can take values 0, 1, 2, 3
d can take values 0, 1, 2
e can take values 1, 2, 3, 4
and f can take values 0, 1, 2, 3, 4

Total number of odd factors = 2*2*4*3*4*5 = 960

Option 4)

Correct Option: 4 Best Solution (2)

28 Oct 2019 Calendar

Today is Monday. After 160 days, it will be :

OPtion

1) Monday
2) Tuesday
3) Wednesday
4) Thursday
5) Friday
6) Saturday or Sunday
7) Sunday or Monday
8) Saturday
9) Sunday
10) None of these

Solution

160 days = 22 weeks 6 days
Hence if today is Monday, After 160 days, it will be = (Monday + 6 days)
= Sunday

Correct Option: 9 Best Solution (5)

25 Oct 2019 Percentage

Facebook user base grows by 2.1 % every quarter. If the Facebook user-base was 2.32 billion on 31st December 2018, What would be its user base on 30th September 2019?
(Round your results to two decimal places.)

OPtion

1) 2.67 billion
2) 2.57 billion
3) 2.37 billion
4) 2.87 billion
5) 2.47 billion
6) 2.49 billion
7) 2.51 billion
8) 2.61 billion
9) 2.63 billion
10) None of these

Solution

2.32 * (1.021)^3 = 2.469 = 2.47

Correct Option: 5 Best Solution (3)

24 Oct 2019 Area

If the diagonal of a rectangle is 23cm long and its perimeter is 52 cm. Find the area of the rectangle in sq. cm.

OPtion

1) 73.5
2) 147
3) 148
4) 150
5) 140
6) 144
7) 145
8) 77.5
9) 74.5
10) None of these

Solution

Let length = x and breadth = y then

2(x+y) = 52
=> x+y = 26
x²+y² = 23² = 529
now (x+y)² = 26² = 676
=> x²+y²+2xy= 676
=> 529 + 2xy = 625
=> xy = 73.5
area = xy = 73.5 sq.cm

Option 1)

Correct Option: 1 Best Solution (6)

23 Oct 2019 Series

Whats the next alphabet of following series:
B,
C,
E,
G,
K,
M,
Q,
?

OPtion

1) R
2) S
3) T
4) U
5) V
6) W
7) X
8) Y
9) Z
10) None of these

Solution

The numbers corresponding to the letter sequence are the prime numbers:

B, C, E, G, K, M, Q, S =
2, 3, 5, 7, 9, 13, 17, 19

Correct Option: 2 Best Solution (3)

22 Oct 2019 Next Term

HY, JU, LQ, NM, ?

OPtion

1) QJ
2) QL
3) QI
4) QK
5) OJ
6) OI
7) OK
8) PK
9) PI
10) None of these

Solution

The first letter of the given series is formed by adding 2 letters
So H+2 = J, J+2 = L, L+2= N, N+2 = P
2nd letter is formed in the revers direction by subtracting 4 letters
So Y - 4 = U, U - 4 = Q, Q - 4 = M, M - 4 = I

PI

Correct Option: 9 Best Solution (2)

21 Oct 2019 Speed

Ram starts his journey from Sri Lanka to Ayodhya on 8th October 2019. Given the fact that the distance between Sri Lanka and Australia is 3146 KMs. Given that he covers 6.6 KMs every hour. How long will it take him to reach Ayodhya?

OPtion

1) 467.67 hours
2) 476.76 hour
3) 476 hours 67 minutes
4) 476 hours 45 minutes
5) 476 hours 40 minutes
6) 20 days
7) 18.86 days
8) 19.16 days
9) 476.87 hours
10) None of these

Solution

Speed per hour = 6.6 KM/hr
Time taken = Distance / Speed = 3146/6.6 = 476.67 hours = 476 hours 40 minutes = 19.86 days

Correct Option: 5 Best Solution (2)