M4maths Previous Puzzles

30 Sep 2010 Possible number

How many number plates are possible, which contain 3 alphabets followed by 3 numbers from 0 to 9?
000 is not allowed in any number plate.

OPtion

1) 676
2) 1752
3) 19234524
4) 6
5) 34256
6) 3450
7) 456
8) 17558424
9) 17576
10) 17576000

Solution

Total number plates = 26*26*26*10*10*10 = 17576000
Number plates containing 000 = 26*26*26 = 17576
Hence required number plates = 17576000 – 17576

Correct Option: 8 Best Solution (13)

29 Sep 2010 Find the next number

234, 506, 2536, 6626, ?

OPtion

1) 6516
2) 9516
3) 4573
4) 39676
5) 26446
6) 36654
7) 39586
8) 36246
9) 45367
10) none

Solution

234=> 4 9 16 => 4 10 6 => 506
506=> 25 0 36 => 25 3 6 => 2536
2536 => 4 25 9 36 => 4 25 12 6=> 4 26 2 6 => 6626
6626 => 36 36 4 36 => 36 36 7 6 => 39 6 7 6 => 39676

Correct Option: 4 Best Solution (2)

28 Sep 2010 Find the sides?

How many sides of a polygon of 20 diagonals?

OPtion

1) 7
2) 8
3) 9
4) 6
5) 10
6) 11
7) 12
8) 13
9) 14
10) 5

Solution

if number of sides are s,
The number of diagonals D = s(s-3)/2
by solve this equation 40 = s^2-3s
By solve this we get s = 8, -5
so the number of sides are 8

Correct Option: 2 Best Solution (16)

27 Sep 2010 3 digit Odd Numbers

How many 3 digit odd number can be formed from the digits 1,3,7,0 and 4?

OPtion

1) 23
2) 25
3) 60
4) 35
5) 85
6) 70
7) 85
8) 55
9) 100
10) 62

Solution

First digit can be any of 1,7,3,4 => 4
second digit can be any of 1, 3,7,0,4 =>5
for a odd number last digit can be any of 1,3,7 =>3
total number of digits are => 4*5*3
60

Correct Option: 3 Best Solution (11)

24 Sep 2010 Find the diffrence

What is the difference between (110 % of 110 % of 110% of 110 % of 100) and (140 % of 100)?

OPtion

1) 0
2) 6.41
3) 8.74
4) 3.48
5) 2.48
6) 4.29
7) 5.88
8) 9.87
9) 7.61
10) 5

Solution

First no. is 100 * 1.1 * 1.1 * 1.1 * 1.1 = 146.41
Second no. is 100 * 1.4 = 140

Correct Option: 2 Best Solution (4)

23 Sep 2010 All men probability?

3 persons have to be selected out of 4 men and 4 women. Probability that all selected persons are men is

OPtion

1) 6/19
2) 1/6
3) 2/13
4) 1/2
5) 3/4
6) 5/6
7) 1/14
8) 1/3
9) 1/4
10) 4/5

Solution

No. of methods of selecting 3 men out of 4 are 4*3*2/3*2*1 = 4
No. of methods of selecting 3 out of total 8 persons are 8*7*6/3*2*1 = 56
Hence probability = 4/56 = 1/14

Correct Option: 7 Best Solution (1)

22 Sep 2010 Find the number of zero?

Find then number of 0 from 1 to 10000 series?

OPtion

1) 2700
2) 2893
3) 2980
4) 180
5) 2986
6) 3098
7) 4536
8) 2145
9) 1235
10) 2098

Solution

In 2 digit numbers : 9,

In 3 digit numbers : 18 + 162 = 180,

In 4 digit numbers : 2187 + 486 + 27 = 2700,

total = 9 + 180 + 2700 + 4 = 2893

Correct Option: 2 Best Solution (4)

21 Sep 2010 Natural number

A positive natural no is 6 less then its square. Cube of the no is

OPtion

1) 8
2) 64
3) 125
4) 216
5) 343
6) 512
7) 729
8) 1331
9) 1000
10) 27

Solution

According to given condition
x2 – 6 = x
x2 – x – 6 = 0
(x – 3)(x + 2) = 0
x = 3, - 2

Correct Option: 10 Best Solution (21)

20 Sep 2010 Next number

199, 296, 391, 484, ?

OPtion

1) 581
2) 576
3) 525
4) 567
5) 575
6) 564
7) 665
8) 595
9) 645
10) 543

Solution

199 => 1+99 = 100
296 => 2^2+96 = 100
391=> 3^2+91 = 100
575 => 5^2+75 = 100

Correct Option: 5 Best Solution (8)

17 Sep 2010 Find the next number

81, 0, 21, 44, ?

OPtion

1) 54
2) 64
3) 69
4) 64
5) 87
6) 94
7) 96
8) 55
9) 77
10) 82

Solution

9, 10, 11, 12, 13
81, 100, 121, 144, 169
take only last 2 digit
81, 0, 21, 44, 69

Correct Option: 3 Best Solution (0)