M4maths Previous Puzzles

02 Sep 2011 number

How many numbers can be formed by using any 6 non zero digits. Repetition of digits is not allowed.

OPtion

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

Solution

answer is 9*8*7*6*5*4 = 7*5*(3^3)*(2^6)

Correct Option: 5 Best Solution (5)

01 Sep 2011 inequality

a+b+c>9 and b+c>6 then least possible value of a for any value of b and c is

OPtion

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

Solution

least possible value means the value which satisfies the condition a+b+c even for the least sum of b and c so only 3 is possible

Correct Option: 3 Best Solution (0)

31 Aug 2011 business

A man invests 11 lacs in two business. In one business he finds a profit of 60 % whereas in second a loss of 50 %. How much his invest would be in the two business if it is given that he got no profit no loss.

OPtion

1) 4 lacs in first business
2) 5 lacs in first business
3) 7 lacs in second business
4) 4 lacs in second business
5) 5 lacs in second business
6) 6 lacs in first business
7) 3 lacs in first business
8) 3 lacs in second business
9) 8 lacs in first business
10) none of these

Solution

according to the given condition
x*0.6 = (11-x)*0.5
or 0.6x = 5.5 - 0.5x
or 1.1x = 5.5
or x = 5 lacs

Correct Option: 2 Best Solution (9)

30 Aug 2011 banana

A man paid a certain amount to buy 24 dozens banana. If the rate of banana would be 4 rupee more for each dozen, then he bought as many dozens as was the previous rate. Total investment of the man was

OPtion

1) 10
2) 14
3) 18
4) 20
5) 24
6) 30
7) 36
8) 40
9) 50
10) none of these

Solution

let the cost of 1 dozen = x
then according to the given condition
24 x = x (x+4)
or x = 20
So total investment = 20*24 = 480

Correct Option: 10 Best Solution (2)

29 Aug 2011 sequence

5, 13, 25, 41, 61 , ......
next number will be

OPtion

1) 85
2) 100
3) 130
4) 74
5) 89
6) 102
7) 94
8) 140
9) 200
10) none of these

Solution

5 = 1 + 4 (sum of squares of two perfect integers)
13 = 4 + 9
25 = 9 + 16
41 = 16 + 25
61 = 25 + 36
next will be 36 + 49 = 85

Correct Option: 1 Best Solution (10)

26 Aug 2011 coin

In a game a man first throws a coin. If he gets head then he puts a card from a deck of 52 cards. Find the probability to get a King of red color.

OPtion

1) 1/2
2) 1/4
3) 1/8
4) 1/26
5) 1/52
6) 13/50
7) 3/4
8) 1/10
9) incomplete data
10) none of these

Solution

Probability to get a head = 1/2
Probability to get a red King = 2/52
so required probability = (1/2)*(2/52) = 1/52

Correct Option: 5 Best Solution (14)

25 Aug 2011 sound

The depth of a well is 999 m. A man throws a stone in the well at a speed of 37 m/s. After how much time he will hear the sound of splash. Speed of sound is given as 333 m/s. The process is undergone in a gravity free space.

OPtion

1) 3 sec.
2) 10 sec.
3) 12 sec.
4) 15 sec.
5) 27 sec.
6) 30 sec.
7) 36 sec.
8) 45 sec.
9) 57 sec.
10) 60 sec.

Solution

time taken for the down motion of stone = 999/37 sec. = 27 sec.
time taken for the up motion of the sound = 999/333 sec. = 3 sec.
total sec. = 27 + 3 = 30

Correct Option: 6 Best Solution (0)

24 Aug 2011 arrangement

There are 8 boys and 10 girls. How many methods are possible to place all of them in such a way so that no two girls could sit together.

OPtion

1) 10
2) 8
3) 90
4) 45
5) 56
6) 80
7) 28
8) 40
9) 100
10) none of these

Solution

if we place 8 boys then we will get 9 places among these boys, but girls are 10, so it is impossible to place them according to the condition given. so answer is 0

Correct Option: 10 Best Solution (7)

23 Aug 2011 bank balance

An old man distributed his bank balance of 60 lacs among three of his children. The eldest one was his daughter and other two were boys. He distributed his money in such a way that daughter got half as many lacs as her age whereas boys got lacs equal to their ages respectively. If difference of the ages between the children is 5, then sum of their ages will be

OPtion

1) 60
2) 65
3) 70
4) 75
5) 80
6) 85
7) 90
8) 95
9) 100
10) 105

Solution

according to the given condition
x/2 + y + z = 60
and x - y = 5, y - z = 5
on solving we will get x = 30, y = 25, z = 20

Correct Option: 4 Best Solution (9)

22 Aug 2011 Find the next number

1,1,2,6,24,120,?

OPtion

1) 240
2) 136
3) 760
4) 720
5) 600
6) 960
7) 560
8) 650
9) 700
10) none of these

Solution

1*1
1*2
2*3
6*4
24*5
120*6 = 720

Correct Option: 4 Best Solution (15)