M4maths Previous Puzzles

10 Jun 2010 Book thickness

The thickness of the page of a book is 0.004 inch. Total thickness (measured in cm.) of the book having 450 pages is
(Given that 1 inch = 2.54 cm.)

OPtion

1) 2.544
2) 5.468
3) 3.432
4) 1.8
5) 4.572
6) 3.8
7) 4.444
8) 2.324
9) 4.984
10) 2.340

Solution

Total thickness of the book = 450 * 0.004 * 2.54 = 4.572 cm.

Correct Option: 5 Best Solution (0)

09 Jun 2010 Investment and Profit

Rahim and Rahman start a business with 10000 rupee investment.Investment of Rahman is 6000 rupee.
After 1 year Rahim invests 10000 again. If profit is 21000 after 5 years, then profit of Rahman is

OPtion

1) 7200
2) 14000
3) 14500
4) 15000
5) 8500
6) 5800
7) 7000
8) 12000
9) 16000
10) 10000

Solution

Investment of Rahim in 5 years = 4000 + 4*14000 = 60000
And investment of Rahman in 5 years = 6000*5 = 30000
Hence profit of Rahman = 30000 * 21000 / (60000 + 30000) = 7000

Correct Option: 7 Best Solution (5)

08 Jun 2010 cylindrical tank volume?

Total volume of a cylindrical tank (in litres), whose internal radius is 10 feet and height is 20 feet is
(Given that 1 inch = 2.54 cm, 1000 cm3 = 1 litre and volume of a cylinder = 22 * (radius) 2 * height / 7)

OPtion

1) 177991
2) 178934
3) 187654
4) 156789
5) 122345
6) 210324
7) 199876
8) 188765
9) 198763
10) 201002

Solution

Volume of a cylinder = 22 * (radius) 2 * height / 7
On taking all the values, we get V = 177991.61 litres

Correct Option: 1 Best Solution (3)

07 Jun 2010 Maths Calculation

3 + [4 – {6 ÷ (4 – 2)} * 5] = ?

OPtion

1) 8
2) -3
3) -8
4) -4
5) 2.5
6) 9.5
7) -9.5
8) -10
9) 6.4
10) 4

Solution

3 + [4 – {6 ÷ (4 – 2)} * 5]
= 3 + [4 – {6 ÷ 2} * 5]
= 3 + [4 – 3* 5]
= 3 + [4 – 15]
= 3 + [– 11]
= 3 – 11
= -8

Correct Option: 3 Best Solution (0)

04 Jun 2010 find the value

If x / y = 5 / 3
Then, (x2 +y2 + 2xy) / ( x2 +y2 - 2xy) = ?

OPtion

1) 25/16
2) 15
3) 12
4) 9
5) 8
6) 4
7) 16
8) 64
9) 2
10) 5/3

Solution

(x2 +y2 + 2xy) / ( x2 +y2 - 2xy) = (x + y)2 / (x – y)2
= (5+3)2 / (5-3)2
= 64/4
=16

Correct Option: 7 Best Solution (5)

03 Jun 2010 probability to letter post?

There are 4 letters, 1 for Sharmaji, 1 for vermaji and 1-1 for Agrawalji and puriji. These letters are enveloped
without writing address. If letter of Sharmaji is posted correctly, then the probability that all the letters posted correctly is

OPtion

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

Solution

If letter of Sharmaji is posted correctly, then possibilities for other letters are 3*2*1 = 6
In these possibilities only 1 has all the letters posted correctly. Hence probability = 1/6

Correct Option: 8 Best Solution (6)

02 Jun 2010 Real value of x

If x2 +2x +2 < 0
Then total no. of real possible values of x is

OPtion

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

Solution

x2 +2x +2 < 0 implies that (x +1)2 +1 < 0
Since equation above is not possible for any real number, hence no answer is obtained

Correct Option: 1 Best Solution (10)

01 Jun 2010 Sum of all possible x

If x + y < 9 and 3 x – 2 y < 3
then sum of all possible values of x is (Given that x > 0) ?

OPtion

1) 10
2) 15
3) 21
4) 28
5) 36
6) 9
7) 12
8) 16
9) 7
10) 6

Solution

According to first condition given
x + y < 9
Implies that y < 9 - x
Implies that 2 y < 18 – 2 x
Implies that 2 y + 3 < 18 – 2 x + 3
Implies that 2 y + 3 < 21 – 2 x (i)
Now according to second given condition
3 x -2 y < 3
Implies that 3 x < 2 y + 3 (ii)
Adding (i) and (ii) conditions, we get
3 x < 2 y + 3 < 21 – 2 x
Implies that 3 x < 21 – 2 x
Implies that 5 x < 21
Hence possible integral values of x = 1, 2, 3, 4
sum of 1+2=3+4 = 10

Correct Option: 1 Best Solution (8)

31 May 2010 Age Difference?

The dates of birth of two persons are 16-02-1983 and 23-11-1977. The difference of their ages is?

OPtion

1) 6y 6m 17d
2) 5y 4m 21d
3) 6y 2m 12d
4) 5y 2m 23d
5) 5y 4m 23d
6) 5y 10m 19d
7) 6y 4m 22d
8) 6y 9m 14d
9) 6y 5m 29d
10) 5y 8m 20d

Solution

The date of birth of first person is 16/2/83; it is equivalent to 46/13/82
And that of second is 23/11/77
On subtracting, we get 23d/2m/5y

Correct Option: 4 Best Solution (7)

28 May 2010 Rod in room?

Length, breadth and height of a room are 20 feet, 15 feet and 10 feet respectively. Maximum length (in integer)
of a rod placed in the room is

OPtion

1) 32
2) 25
3) 24
4) 27
5) 28
6) 29
7) 30
8) 31
9) 26
10) 23

Solution

Diagonal is the greatest length inside the room, its value = (20^2+15^2+10^2)^1/2 = (725)^1/2
= 26.926 = 26 in integer form

Correct Option: 9 Best Solution (8)