M4maths Previous Puzzles

21 Jan 2010 number greater then 57,26,000?

A seven digit number is formed by using the digits 3, 3, 4, 5, 5, 8 & 9. Probability that the number formed
is great than 57,26,000 is?

OPtion

1) 3/8
2) 1/5
3) 8/21
4) 2/9
5) 12/35
6) 16/35
7) 8/35
8) 1/3
9) 2/5
10) 9/35

Solution

Total no. of numbers formed by using the given digits 3,3,4,5,5,8,9 = (7*6*5*4*3*2*1)/(2*1)*(2*1) = 1260

(Denominator part is due to the repetition of 3 and 5)

Total no. of numbers formed by using the given digits 3,3,4,5,5,8,9 which are greater than 57,26,000 are of two types

Total no. of numbers started with 5 = (2*2*5*4*3*2*1)/ (2*1)*(2*1) = 120
Total no. of numbers started with 8&9 = (2*6*5*4*3*2*1)/ (2*1)*(2*1) = 360
Hence required probability = (120 + 360)/ 1260 = 480/1260 = 8/21

Correct Option: 3 Best Solution (7)

20 Jan 2010 Next Number?

Next number of the sequence 10, 16, 26, 41, 62 is

OPtion

1) 94
2) 88
3) 86
4) 87
5) 89
6) 91
7) 92
8) 93
9) 85
10) 90

Solution

Difference of successive numbers are 6, 10, 15, 21,....
6 = 1+2+3
10 = 1+2+3+4
15 = 1+2+3+4+5
21 = 1+2+3+4+5+6
Hence next difference is 1+2+3+4+5+6+7 = 28

Correct Option: 10 Best Solution (7)

19 Jan 2010 Marks in 6 subject

The average marks for 5 subjects is 62. If average of 6 subjects is 63. Then what will be
the difference between marks of 6th subject and average of 5 subjects.

OPtion

1) 5
2) 6
3) 12
4) 18
5) 1
6) 10
7) 15
8) 12.6
9) 10.5
10) 9

Solution

Total marks for first five subjects are 62*5 = 310
Total marks for six subjects are 63*6 = 378
Marks for sixth subject are 378 – 310 = 68
Difference is 68 – 62 = 6

Correct Option: 2 Best Solution (4)

18 Jan 2010 Discount offer

What will be the difference of cost of an object of 1000 rupee if a discount of 10% +10% +10%
is provided by the first shopkeeper and 30% by the other.

OPtion

1) 10
2) 30
3) 0
4) 29
5) 20
6) 11.1
7) 25
8) 28
9) 9
10)27

Solution

In first case the price of the object is 1000* 0.9* 0.9* 0.9 = 729
In second case it is 1000* 0.7 = 700
Difference is 729 – 700 = 29

Correct Option: 4 Best Solution (3)

15 Jan 2010 % profit approx ?

A packet of toffee contains 57 toffees. The cost of packet is 44 rupee but every toffee is sold in 1 rupee separately.
Find the percentage profit on selling the toffees one by one relative to sell the packet.

OPtion

1) 25
2) 35
3) 40
4) 30
5) 20
6) 45
7) 37
8) 28
9) 22
10) 18

Solution

{(57/44)*100} – 100 = 29.55 (approx 30)

Correct Option: 4 Best Solution (5)

14 Jan 2010 Leap year Intrest ?

What will be the interest of 1 day of 10500 rupee at a rate of 6.25 % yearly in a leap year

OPtion

(1) 4.00
(2) 2.00
(3) 8.60
(4) 6.70
(5) 3.00
(6) 5.40
(7) 9.30
(8) 1.80
(9) 2.50
(10) 3.60

Solution

Daily interest rate = 6.25/366 %
Hence Interest = {10500 * (6.25/366) * 1}/100 = 1.80

Correct Option: 8 Best Solution (5)

13 Jan 2010 saving plan

What will be the difference of the amounts in the two types of saving given below
1) 10 rupee per day upto 100 days
2) 25 paisa then 50 paisa then 75 paisa then so on upto 100 days

OPtion

(1) 300.00
(2) 250.00
(3) 262.50
(4) 152.50
(5) 98.50
(6) 67.00
(7) 275.00
(8) 122.00
(9) 230.00
(10) 200.50

Solution

In first saving total amount = 1000 rupee
In second, savings of 50th and 51st days are 12.50 and 12.75 rupee
(These two are middle terms)
Total saving in second case = 100*{(12.50 + 12.75)/2} = 1262.50 rupee
Difference is 262.50 rupee

Correct Option: 3 Best Solution (5)

12 Jan 2010 square vs circle

A wire of length 20 cm. is turned to form a
1) square 2) circle
Find out the ratio of side of the square and radius of the circle
(Given Π = 3.14)

OPtion

(1) 0.32
(2) 3.14
(3) 0.64
(4) 1.57
(5) 2.00
(6) 1.75
(7) 4.13
(8) 0.99
(9) 1.00
(10) 0.50

Solution

Since same wire is used to form square and circle , therefore
Perimeter of square = Circumference of circle
4 Side = 2 Π R
Hence Side / R = 1.57

Correct Option: 4 Best Solution (6)

11 Jan 2010 ratio of number?

What will be the ratio of a number obtained by taking the following two steps alternatively in a number and
the number itself
1) Number is decreased by 20 %
2) Number is increased by 20 %

OPtion

(1) 0.98
(2) 1.00
(3) 1.20
(4) 0.80
(5) 1.08
(6) 1.04
(7) 0.96
(8) 0.92
(9) 0.90
(10) 1.10

Solution

Let the number is x
On taking these two operations alternatively, we get the new number as
x*0.8*1.2 = 0.96x
Hence the ratio is 0.96

Correct Option: 7 Best Solution (4)

08 Jan 2010 vodafone offer

There are two schemes in Vodafone mobiles.

First scheme :1 paise per second,

Second scheme :50 paise per minute,

Following conditions are given -

1. In second scheme, second minute will be started at 0:60 or 1:00,

2. 0 sec. call means to call and cut it abruptly when timer reads 0:00, this is equivalent to a call of 1 sec.

3. In first scheme 0:14 means 15 sec.

The probability that first scheme is more profitable over second in a call ranging from 0:00 (1 sec.) to 3:20 (201 sec.) is ?

OPtion

1) 136/201
2) 139/201
3) 139/200
4) 4/25
5) 17/50
6) 17/25
7) 100/201
8) 1/2
9) 1/4
10) 1

Solution

The ranges in which first scheme is more profitable over second in a call ranging from 0:00 (1 sec.) to 3:20 (201 sec.) is –

0-48, 60-98, 120-148, 180-198,

Hence total seconds in which first scheme is more profitable over second are 136.
Therefore probability that first scheme is more profitable over second in a call ranging
from 0:00 (1 sec.) to 3:20 (201 sec.) is 136/201.

Correct Option: 1 Best Solution (0)