M4maths Previous Puzzles

20 Jan 2012 building

There is a 4 storied building. In every floor 4 sets are available so total 16 room sets are available. I have to knock 3 out of these 16 for finding the room of my friend. What will be the probability to get the friends room?

OPtion

1) 13*14*15/16*16*16
2) 1/16*16*16
3) 15/16
4) 1/16
5) 1/8
6) 3/16
7) 13/16
8) 7/8
9) 1/2
10) none of these

Solution

probability of failure = (15/16)(14/15)(13/14) = 13/16
so probability of success = 1 - 13/16 = 3/16

Correct Option: 6 Best Solution (4)

19 Jan 2012 solve

sqrt(1) % of sqrt(1) + sqrt(3) % of sqrt(3) + sqrt(5) % of sqrt(5) + .....................+ sqrt(999999) % of sqrt(999999)

OPtion

1) 25*10^4
2) 25*10^6
3) 25*10^8
4) 64*10^4
5) 64*10^6
6) 64*10^8
7) not possible to solve
8) more than 10^40
9) less than 10^5
10) none of these

Solution

sqrt(x) % of sqrt(x) = x/100
besides it 1+3+5+7+.............+upto n terms = n^2
apply it and get the answer

Correct Option: 3 Best Solution (8)

18 Jan 2012 time

choose the incorrect one

OPtion

1) 7:15:12 AM
2) 7:16:04 AM
3) 7:16:56 AM
4) 7:17:48 AM
5) 7:18:40 AM
6) 7:19:32 AM
7) 7:20:24 AM
8) 7:21:18 AM
9) 7:22:08 AM
10) none of these

Solution

all the differences are 52 minutes except 8th.

Correct Option: 8 Best Solution (7)

16 Jan 2012 age

Sum of the ages of Surendra and Mahendra is 74. If difference of their ages ranges from 6 to 12 (only integers), then total number of possible answers are. (All ages are integral values only). Consider that Surendra is elder than Mahendra.

OPtion

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

Solution

Possible answers are (40,34), (41,33), (42,32), (43,31)

Correct Option: 4 Best Solution (15)

13 Jan 2012 elephant

How many words of 8 letters can be formed by using all alphabets leaving alphabet used in the word ELEPHANT.(Revision of letters in the word is not allowed.)

OPtion

1) 3047466240
2) 3045466240
3) 3046657889
4) 152
5) 75582
6) 440
7) 123420
8) 19
9) 110
10) none of these

Solution

ELEPHANT has total 7 different letters
so remaining letters = 26-7 = 19
so possible words = 19*18*17*16*15*14*13*12

Correct Option: 1 Best Solution (0)

12 Jan 2012 percentage

k % of m = n % of x
so x will be

OPtion

1) kn/m
2) mn/k
3) km/n
4) 1/kmn
5) kmn
6) k/m
7) n/m
8) m/n
9) 1/k
10) none of these

Solution

k % of m = n % of x
=> km/100 = nx/100
=> x = km/n

Correct Option: 3 Best Solution (0)

11 Jan 2012 inequalities

x+y+z=19
1 < x < 5, 4 < y <8, 10 < z < 14
How many outcomes are possible for integral values of x, y and z

OPtion

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

Solution

according to the given conditions
possible values of x, y and z are
x = 2, 3, 4
y = 5, 6, 7
z = 11, 12, 13
so possible combinations are
(2, 5, 12), (2, 6, 11), (3, 5, 11)

Correct Option: 3 Best Solution (17)

10 Jan 2012 age

Ram says to Shyam that his age is one and half times that of Shyam's age yet it was twice the age of Shyam 10 years before. Calculate the sum of their ages.

OPtion

1) 10
2) 30
3) 45
4) 50
5) 55
6) 65
7) 70
8) 80
9) 90
10) none of these

Solution

According to the given conditions
r = 3s/2
r-10 = 2(s-10)
on solving we get r = 30 and s = 20
so sum = 50

Correct Option: 4 Best Solution (0)

09 Jan 2012 sequence

next number of the sequence 6, 13, 32, 69, 130, .......... will be

OPtion

1) 221
2) 242
3) 254
4) 261
5) 287
6) 299
7) 301
8) 339
9) 400
10) none of these

Solution

the sequence is 1^3 + 5 = 6, 2^3 + 5 = 13
similarly for others

Correct Option: 1 Best Solution (10)

06 Jan 2012 integers

The sum of 3 integers is 16. How many outcome are possible. All integers are lying between 3 to 9.

OPtion

1) 6
2) 8
3) 10
4) 12
5) 15
6) 18
7) 20
8) 21
9) 25
10) none of these

Solution

integers are lying between 3 to 9, it means these integers are 4,5,6,7 and 8.
possible combinations are
4,4,8 (3 possibilities)
4,5,7 (6 possibilities)
4,6,6 (3 possibilities)
5,5,6 (3 possibilities)

total possibilities = 15

Correct Option: 5 Best Solution (3)