M4maths Previous Puzzles

29 Apr 2011 Bench

There are two benches in an office.The capacity of these two benches are 4 and 3 persons respectively.How many methods are possible for making a sitting arrangement of 7 persons in these two benches.

OPtion

1) 720
2) 24
3) 120
4) 5040
5) 35
6) 21
7) 20
8) 96
9) 108
10) 4032

Solution

Since benches are straight.so total methods are 7*6*5*4*3*2*1 = 5040

Correct Option: 4 Best Solution (0)

28 Apr 2011 probability

A person goes to office either by car, jeep, bus or train. The probabilities of which being 2/7, 3/7, 1/7 ,1/7 respectively. The probability that he reaches office later if he takes jeep, bus, car or train is 2/9, 1/9, 5/9, 2/9 respectively. If he reaches office in time, then the probability that he travelled by car is

OPtion

1) 2/7
2) 2/11
3) 4/13
4) 4/15
5) 7/19
6) 8/21
7) 9/19
8) 10/21
9) 11/32
10) 12/31

Solution

the probability that he travelled by car is 2/7
The probability that he reaches office later if he takes car is 5/9
So probability that he reaches office in time by car =(2/7)*(4/9)= 8/63
Similarly probability for jeep = (3/7)*(7/9) = 21/63
Similarly probability for bus = (1/7)*(8/9) = 8/63
Similarly probability for train = (1/7)*(7/9) = 7/63
so required probability = (8/63)/(8/63)+(21/63)+(8/63)+(7/63)= 8/44 = 2/11

Correct Option: 2 Best Solution (0)

27 Apr 2011 Average

The sum of 99 numbers is 1958. What will be the number required to add in this sum to get the average of all the numbers 20.7

OPtion

1) 108
2) 112
3) 118
4) 146
5) 179
6) 195
7) 230
8) 270
9) 298
10) 324

Solution

Average of 100 numbers = 20.7
Thus total
sum of 100 numbers = 2070
Sum of 99 numbers = 1958
New number = 2070 - 1958 = 112

Correct Option: 2 Best Solution (9)

26 Apr 2011 what will be the next

2 6 12 20 30 ?

OPtion

1) 40
2) 41
3) 42
4) 38
5) 56
6) 50
7) 44
8) 48
9) 64
10) 60

Solution

1*2 = 2
2*3 = 6
3*4 = 12
4*5 = 20
5*6 = 30
6* 7 = 42

Correct Option: 3 Best Solution (3)

25 Apr 2011 what will be the value of 8!

if 6! = 21
and 2! = 3
then what would be the 8!

OPtion

1) 34
2) 36
3) 40320
4) 34567
5) 87
6) 24
7) 30
8) 42
9) 96
10) 286

Solution

here 6!=6+5+4+3+2+1 = 21
so 8! = 8+7+6+5+4+3+2+1 = 36

Correct Option: 2 Best Solution (16)

22 Apr 2011 Permutation

How many 4 or 5 digit numbers can be formed by using 0, 1, 3, 5, 8. Repetition is not allowed.

OPtion

1) 192
2) 96
3) 81
4) 72
5) 64
6) 54
7) 48
8) 36
9) 25
10) 16

Solution

for 4 digit number
total case are 4*4*3*2 = 96
and for 4 digit number
4*4*3*2*1 = 96

total number are 192

but the option was printed wrong so we give marks to all the user.

Correct Option: 1 Best Solution (2)

21 Apr 2011 Train

Two trains are moving with speeds 40 km/hr and 50 km/hr in same direction. Train with speed 40 km/hr is 30 km ahead of the second train.
Total path required for making a meeting of the two trains is

OPtion

1) 90 km
2) 100 km
3) 110 km
4) 120 km
5) 130 km
6) 140 km
7) 150 km
8) 160 km
9) 170 km
10) 180 km

Solution

3 hrs are required for meeting , so total path required = 50*3 = 150 km

Correct Option: 7 Best Solution (5)

20 Apr 2011 Find the next

A D I P

OPtion

1) R
2) Y
3) Z
4) U
5) X
6) T
7) V
8) Q
9) M
10) N

Solution

A(1), D(4), I(9), P(16), 25-Y

Correct Option: 2 Best Solution (9)

19 Apr 2011 probability

What will be the probability of selecting 2 integers with same unit's place in such a way that the unit's place of the product of these 2 integers would be same as that of the given integers

OPtion

1) 1/2
2) 2/3
3) 4/5
4) 5/8
5) 16/19
6) 1/25
7) 2/27
8) 3/32
9) 4/35
10) 5/39

Solution

Possible unit's place are 0, 1, 5, 6
So probability = (4/10)* (1/10) = 1/25

Correct Option: 6 Best Solution (0)

18 Apr 2011 Find the next

1,4,27,256, 3125, 46656

5, 31, 283, 3381, ?

OPtion

1) 46656
2) 46578
3) 49781
4) 33911
5) 56747
6) 44444
7) 67567
8) 12376
9) 49786
10) 29878

Solution

1^1, 2^2, 3^3, 4^4, 5^5, 6^6

1,4,27,256,3125,46656
1+4, 4+27, 27+256, 256+3125, 3125+46656
= 49781

Correct Option: 3 Best Solution (11)