M4maths Previous Puzzles

02 Sep 2010 Find the X

36 % of a number x is 64 % of 90. x is?

OPtion

1) 234
2) 158
3) 154
4) 150
5) 148
6) 142
7) 160
8) 218
9) 198
10) 176

Solution

36x/100 = 90(64)/100
Hence x = 90(64)/36 = 160

Correct Option: 7 Best Solution (2)

01 Sep 2010 Number and its reverse

The difference of a number of two digit and a number formed by reversing its digit is 54. The number is

OPtion

1) 73
2) 83
3) 92
4) 51
5) 48
6) 38
7) 80
8) 91
9) 71
10) 27

Solution

60 – 06 = 54
71 – 17 = 54
82 – 28 = 54
93 – 39 = 54

Correct Option: 9 Best Solution (15)

31 Aug 2010 girls and boys

No. of methods to place 3 boys and 4 girls in a row in such a way that neither two girls G1, G2
nor two boys B1, B2 are taken together are

OPtion

1) 2480
2) 1440
3) 1580
4) 1280
5) 2160
6) 2360
7) 2920
8) 2540
9) 2280
10) 2090

Solution

There are three other members besides B1, B2, G1 and G2.
Methods to place these three members = 3.2.1
After then methods to place two boys between them = 4.3
Then methods to place two girls between them = 6.5
Total methods = 3.2.1.4.3.6.5 = 2160

Correct Option: 5 Best Solution (2)

30 Aug 2010 Find the value

40 % of 40 % of 40 is ?

OPtion

1) 16
2) 8.8
3) 12
4) 6.4
5) 24
6) 9.6
7) 4.8
8) 3.2
9) 12.8
10) 64

Solution

40 * 40/100 * 40/100 = 6.4

Correct Option: 4 Best Solution (23)

27 Aug 2010 clock angle

Angle between minute hand and hour hand of a clock at 5:50 AM is

OPtion

1) 100 degree
2) 120 degree
3) 150 degree
4) 135 degree
5) 115 degree
6) 125 degree
7) 90 degree
8) 110 degree
9) 160 degree
10) 130 degree

Solution

Total angle between number 5 and number 10 in a clock is 150 degree.
Total rotation of hour hand in 50 minute = 30 * 50/60 = 25 degree
Hence required angle = 150 – 25 = 125

Correct Option: 6 Best Solution (3)

26 Aug 2010 Find the sum

Sum of 1, 3, 6, 10, 15, 21....... upto 10 terms

OPtion

1) 231
2) 230
3) 225
4) 345
5) 197
6) 195
7) 220
8) 224
9) 218
10) 204

Solution

1+3+6+10+15+21+.......
=1+(1+2)+(1+2+3)+(1+2+3+4)+(1+2+3+4+5)+.......
= 1*10+2*9+3*8+4*7+5*6+6*5+7*4+8*3+9*2+10*1
=2(10+18+24+28+30)
=220

Correct Option: 7 Best Solution (20)

25 Aug 2010 arrange girl and boy

Total number of methods to arrange 7 girls and 5 boys in a row in such a way that no two girls can sit together ?

OPtion

1) 1
2) 5040
3) 120
4) 0
5) 2
6) 35
7) 12
8) 7
9) 5
10)100

Solution

It is not possible.

Correct Option: 4 Best Solution (11)

24 Aug 2010 3 nonzeo numbers

3 nonzero positive integers x < y < z are such that their sum is 7. The sum of their squares is?

OPtion

1) 20
2) 27
3) 17
4) 37
5) 49
6) 19
7) 21
8) 15
9) 10
10) 30

Solution

Only possible set is 1, 2 and 4

Correct Option: 7 Best Solution (14)

23 Aug 2010 Total Cost?

The cost of a pen and a pencil are 10 rupee and 4 rupee respectively. If a shopkeeper gives a discount of 10 % and 4 %
in the two items respectively. Then total cost of 10 pens and 4 pencils is

OPtion

1) 109.38
2) 104.40
3) 111.36
4) 110.24
5) 105.36
6) 108.46
7) 101.24
8) 99.20
9) 106.28
10) 98.28

Solution

Total cost of pens after taking discount of 10 % = 10 * 10 * 0.9 = 90
Total cost of pencils after taking discount of 4 % = 4 * 4 * .96 = 15.36

Correct Option: 5 Best Solution (6)

20 Aug 2010 Unit place digit?

Digit in the unit place of
3^(3^3) - (3^3)^3 is

OPtion

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

Solution

3^(3^3) – (3^3)^3
3^27 – 27^3
27^9 – 27^3
(27^3)[(27^6)-1]
(....3)*(....9 -1)
(....3)*(....8)
....4

Correct Option: 3 Best Solution (17)