M4maths Previous Puzzles

05 Jul 2012 percentage

1%of 1%of 1%of 1%of 1%of 1%of ................ 1 = 10^-60
How many times 1%of is written in this question

OPtion

1) 21
2) 23
3) 25
4) 27
5) 30
6) 32
7) 33
8) 35
9) 36
10) none of these

Solution

1%of 1 = 0.01 = 10^-2
so for 60 powers, answer will be 30

Correct Option: 5 Best Solution (21)

04 Jul 2012 combinations

How many combinations are possible by using 2 one rupee coin, 3 two rupee coin and 6 five rupee coin. You can take any number of coins at a time but at least one.

OPtion

1) 45
2) 49
3) 56
4) 60
5) 63
6) 69
7) 78
8) 83
9) 94
10) none of these

Solution

total no. of combinations = (2+1)(3+1)(6+1)-1 = 83

Correct Option: 8 Best Solution (0)

03 Jul 2012 5 digit number

Sum of all 5 digit numbers formed by using the digits 1,3,4,6,8

OPtion

1) 5435678
2) 5645798
3) 5866608
4) 6213458
5) 6454388
6) 6657498
7) 7234308
8) 7865078
9) 7965068
10) 8012008

Solution

sum of all the digits = 22
total no. of numbers formed by these 5 digits = 120
so every digit will come 24 times in all the places like unit place, ten place and so on.
now 22*24 = 528
so sum = 5280000+528000+52800+5280+528 = 5866608

Correct Option: 3 Best Solution (0)

02 Jul 2012 sequence

next number of the sequence 3,4,11,66,627,.......will be

OPtion

1) 4538
2) 3490
3) 4582
4) 5683
5) 2949
6) 7778
7) 2194
8) 9586
9) 1249
10) none of these

Solution

3 = 1^0 + 2
4 = 2^1 + 2
11 = 3^2 + 2
66 = 4^3 + 2
so on

Correct Option: 6 Best Solution (0)

29 Jun 2012 number

The difference of a 3 digit positive number and the formed by reversing the digits of the number is 99. Sum of the digits at units and thousands place is 11 and tens place is 1 less then the units place. Product of the 2 numbers will be

OPtion

1) 352170
2) 345460
3) 319780
4) 293440
5) 265470
6) 231430
7) 213470
8) 194580
9) 182330
10) none of these

Solution

let the number is 100x+10y+z
so according to the given condition
(100x+10y+z)-(100z+10y+x) = 99
so x-z = 1
other conditions given are x+z = 11
and y = z-1
on solve this we find x = 6, y = 4 and z = 5
so number is 645

Correct Option: 1 Best Solution (0)

28 Jun 2012 solve

if x - x^2 = x^3 - x^4
then possible values of x are

OPtion

1) 0
2) 1
3) 2
4) 3
5) -1
6) -2
7) -3
8) 2 values out of the given 7 values
9 3 values out of the given 7 values
10) 4 values out of the given 7 values

Solution

x - x^2 = x^3 - x^4
implies that x(1-x) = x^3(1-x)
so (1-x)(x-x^3) = 0
so (1-x)x(1-x^2)= 0
so (1-x)x(1+x)(1-x) = 0
so x = 0, 1, -1

Correct Option: 9 Best Solution (0)

27 Jun 2012 mode

The most probable output is called mode.
What will be the mode of following observations given
4, 9, 7, 9, 5,
8, 2, 1, 4, 8,
6, 7, 5, 4, 8,
8, 4, 9, 3, 3,
3, 0, 1, 4, 7.

OPtion

1) 1
2) 2
3) 3
4) 4
5) 5
6) 6
7) 7
8) 8
9) 9
10) 0

Solution

4 is repeated 5 times so it will be the mode

Correct Option: 4 Best Solution (14)

26 Jun 2012 probability

A day is randomly selected from 18 June 2012 to 25 June 2012.
What will be the probability of the selected day to be Monday.

OPtion

1) 1/2
2) 1/3
3) 1/4
4) 1/5
5) 1/6
6) 2/3
7) 3/4
8) 4/9
9) 0
10) none of these

Solution

Total Monday = 2
Total days = 8
so probability = 2/8 = 1/4

Correct Option: 3 Best Solution (0)

25 Jun 2012 sequence

1, 4, 27, 256, 3125, .......
next number of the sequence will be

OPtion

1) 46656
2) 7776
3) 6296
4) 5216
5) 4436
6) 15625
7) 21024
8) 52048
9) 45676
10) none of these

Solution

the sequence is 1^1, 2^2, 3^3, 4^4, 5^5, 6^6

Correct Option: 1 Best Solution (0)

23 Jun 2012 k k

if k^2 + k < 6
and k > 0
then maximum value of k will be

OPtion

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

Solution

k^2 + k - 6 < 0
(k+3)(k-2) < 0
so -3 < k < 2
since k > 0
so range of k will be (0,2)
so max. of k = 2

Correct Option: 2 Best Solution (2)