M4maths Previous Puzzles

31 Mar 2020 Numbers

Only one two-digit square number has digits which themselves are square numbers.

OPtion

1) 16
2) 91
3) 27
4) 81
5) 64
6) 49
7) 36
8) 18
9) 25
10) None of these

Solution

49 => 7^2
4 => 2^2
9 => 3*2

Correct Option: 6 Best Solution (0)

30 Mar 2020 Series

In the number series 4, 6, 10, 14, 22, 26, 34, 38, What number comes at eleventh place?

OPtion

1) 64
2) 46
3) 58
4) 85
5) 61
6) 31
7) 76
8) 62
9) 82
10) None of these

Solution

Series is of prime number multiplied with 2:
2*2, 3*2, 5*2, 7*2, 11*2, 13*2, 17*2, 19*2, 23*2, 29*2, 31*2,

Correct Option: 8 Best Solution (0)

27 Mar 2020 Number

What is the only counting number that comes between a perfect square number and a perfect cube number?
Note: The 3 numbers should be consecutive numbers (A,B and C) where A is a perfect square, B is the answer which you have to find and C is a perfect cube.

OPtion

1) 65
2) 80
3) 50
4) 48
5) 26
6) 63
7) 45
8) 10
9) 7
10) None of these

Solution

25 is a perfect square 5^2
27 is a perfect cube
And the answer is 26

Correct Option: 5 Best Solution (3)

26 Mar 2020 Series

11, 31, 71, 91, 32, 92, 13, ?

OPtion

1) 102
2) 39
3) 31
4) 93
5) 97
6) 73
7) 49
8) 37
9) 43
10) None of these

Solution

he series above is the mirror image of two digit prime numbers: 11, 13, 17, 19, 23, 29, 31 - the next prime would be 37, and after reversing the digits you get 73

Correct Option: 6 Best Solution (1)

23 Mar 2020 Simple Interest

A sum amounts to Rs 2358 at the rate of 10 %.p.a. in 20 years. What is the sum?

OPtion

1) 716
2) 726
3) 736
4) 786
5) 756
6) 766
7) 776
8) 706
9) 796
10) None of these

Solution

A = P (1+ RT/100 )
2358 = P (1 + 10*20/100)
=> 2358 = P (3)
=> 786

Correct Option: 4 Best Solution (2)

20 Mar 2020 Clock

Whats the angle (in degrees) between the two hands of a clock when the time shown by the clock is 7: 30 p.m.?

OPtion

1) 30
2) 145
3) 155
4) 45
5) 135
6) 60
7) 75
8) 15
9) 42.5
10) None of these

Solution

Angle = (11/2)M – 30H,
where M =30, and H =7

= (11/2)*30 – 30 x 7

= |165 – 210|, taking the mode of the values, we get

= 45 degree

Correct Option: 4 Best Solution (0)

19 Mar 2020 Logarithm

If (log a/b) + log (b/a) = log (a+b) then

OPtion

1) a - b = 1
2) a = b
3) a = -b
4) a = b + 1
5) a = b - 1
6) a^2 - b^2 = 1
7) a = 1 - b
8) a^2 + b^2 = 1
9) a + b = 2
10) None of these

Solution

(log a/b) + log (b/a) = log (a+b)
=> log ((a/b) * (b/a)) = log (a+b)
=> log 1 = log (a+b)
=> a+b =1

Correct Option: 7 Best Solution (2)

18 Mar 2020 Arithmetic

The sum of squares of three successive integers is 99374. Sum of these integers is?

OPtion

1) 440
2) 446
3) 646
4) 546
5) 746
6) 596
7) 576
8) 526
9) 528
10) None of these

Solution

(a-1)^2 + a^2 + (a+1)^2 = 99374
=> a^2 -2a + 1 + a^2 + a^2 + 2a + 1 = 99374
=> 3a^2 + 2 = 99374
=> a^2 = (20174-2)/3 = 33124
=> a = 182
So the 3 numbers are 181, 182 and 183 and their sum is 546

Correct Option: 4 Best Solution (3)

17 Mar 2020 Probability

Raju has toffees of 5 colors kept in a bag: red, yellow, blue, pink and green.
He randomly picks a toffee what would be the probability that it would be of blue color?

OPtion

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

Solution

Total outcomes = 5
Positive outcomes =1
Probability = 1/5

Correct Option: 7 Best Solution (5)

16 Mar 2020 Simple Interest

A sum amounts to Rs 4545 at the rate of 10 %.p.a. in 5 years. In how many years will the same sum amount to three times the value of sum?

OPtion

1) 12
2) 18
3) 16
4) 21
5) 10
6) 15
7) 17
8) 20
9) 24
10) None of these

Solution

A = P (1+ RT/100 )
4545 = P (1 + 5*10/100)
=> 4545 = P (3/2)
=> P = 3030

A = 9090. P= 3030, R=10, T=?
SI = 9090-3030 = 6060


SI=PRT/100

6060 = 3030*10*T/100
=> T = 20

Correct Option: 8 Best Solution (2)