M4maths Previous Puzzles

04 Mar 2011 probability

The probability of, having month of birth of two newly born child same is (taking that every month of a year has 30 days

OPtion

1) 1/2
2) 1/3
3) 1/7
4) 1/12
5) 1/20
6) 1/24
7) 1/30
8) 1/60
9) 1/365
10) 1/900

Solution

Total methods of the happening of the given event are 12
Overall methods are 12*12
so probability = 12/144 = 1/12

Correct Option: 4 Best Solution (0)

03 Mar 2011 average

If average of 8 and a^2 is (2a+2), value of a would be

OPtion

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

Solution

2a + 2 = (8 + a^2)/2
4a + 4 = 8 + a^2
a^2 – 4a + 4 = 0
or (a – 2)^2 = 0
or a = 2

Correct Option: 3 Best Solution (0)

02 Mar 2011 combination

A man has two 1 rupee, one 2 rupee & three 5 rupee coins. How may combinations are possible.

OPtion

1) 5
2) 6
3) 11
4) 12
5) 17
6) 18
7) 23
8) 24
9) 29
10) 30

Solution

Man has two 1 rupee coin, he can take 0 coin, 1 coin, 2 coin so
3 * 2 * 4 = 24
These methods include one method of 0 one rupee coin, 0 two rupee coin and 0 five rupee coin.
so total possible combinations are 24-1 =23

Correct Option: 7 Best Solution (1)

01 Mar 2011 school

240 students of a school are arranged in rows. If 4 students would be less in a row then 3 more rows will be arranged. Initially total no of rows will be.

OPtion

1) 6
2) 8
3) 10
4) 12
5) 15
6) 16
7) 18
8) 20
9) 24
10) 30

Solution

Let no. of rows = x and no. of students in a row = y
According to the given conditions
x.y = 240 (1)
(x+3).(y-4) = 240 (2)
or (x+3).[(240/x)-4] = 240
or (x+3).[240-4x] = 240x
or 240x - 4x^2 + 720 - 12x = 240x
or x^2 + 3x - 180 = 0
or x = 12, -15

Correct Option: 4 Best Solution (12)

28 Feb 2011 x lies between?

x^x = 1296, then x lies between

OPtion

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

Solution

1^1 = 1
2^2 = 4
3^3 = 27
4^4 = 256
5^5 = 3125
by using this we can clearly find out the solution that x lies between 4 and 5

Correct Option: 5 Best Solution (7)

25 Feb 2011 probability

A coin is thrown. If head comes, a coin will be thrown again, otherwise a dice will be thrown. A tail has occurred in a coin, then probability of getting an even number in the dice would be

OPtion

1) 0
2) 1/2
3) 2/3
4) 2/5
5) 1/4
6) 1/6
7) 3/7
8) 3/8
9) 2/9
10) 1/12

Solution

Total cases are
HT, T1, T2, T3, T4, T5, T6
Favorable cases are
T2, T4, T6

Correct Option: 7 Best Solution (0)

24 Feb 2011 Oh life

A man died after having a total life of 22476 days.If his date of birth is 17 July 1861.Then his expire date would be ( consider that the total value of a year is 365 days and 6 hrs)

OPtion

1) 4 june 1923
2) 3 july 1923
3) 29 jan 1923
4) 13 feb 1923
5) 15 feb 1923
6) 4 june 1922
7) 3 july 1922
8) 29 jan 1922
9) 13 feb 1922
10) 15 feb 1922

Solution

22476 days = 61 years (including 15 leap years of 366 days) + 196 days
Total days in the year 1861 counted from 17 july = 168
Remaining days = 28
so it would be 29 jan 1923

Correct Option: 3 Best Solution (6)

23 Feb 2011 average

A train travels 50 km. distance with speed 50 km./hrs and next 50 km. with speed 60 km./hrs. Average speed will be

OPtion

1) 52
2) 50
3) 60
4) 54
5) 55
6) 54.54
7) 55.5
8) 110
9) 27.27
10) 56.65

Solution

Total distance travelled = 100 km.
Total time taken = (50/50) + (50/60) hrs = 11/6 hrs
so average speed = 100/(11/6) = 600/11 = 54.54

Correct Option: 6 Best Solution (17)

22 Feb 2011 Try it

Sum of three positive integer is 12.Product of these 3 integers would be maximum if these numbers are (select any one out of these ten options)

OPtion

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

Solution

If we solve 4*4*4, we would get 64(max) but this option is not present there so out of given 10 options 4+5+3 =12
Product = 60 (max)

Correct Option: 1 Best Solution (14)

21 Feb 2011 sequence

If a sequence is
1, 99, 111, 9999, 11111, ....
Then next integer in the number system of the fifth number in the given sequence would be

OPtion

1) 99999
2) 9999999
3) 999999
4) 222222
5) 11112
6) 111111
7) 99999999
8) 121212
9) 111112
10) 33333

Solution

After 11111, next integer would be 11112

Correct Option: 5 Best Solution (0)