Puzzles for Interviews, Entrance and Competitive Exams Set-3
1. There are 4 married couples, out of which, 3 people in a group is needed. But there should not be his or her spouse in the group. How many groups are possible?
2. In the 4 digits 1,2,3,4, how many 4 digited numbers are possible which are divisible by 4? Repetitions are allowed.
3. Two men are going along a track of rail in the opposite direction. One goods train crossed the first person in 20 sec. After 10 min the train crossed the other person who is coming in opposite direction in 18 sec. After the train has passed, when the two persons will meet?
Ans: Approx. 72 min, check it once.
4. The no. of children, adults. The no. of adults the no. of boys. The no. of boy’s no. of girls. The no. of girl’s no. of family. Conditions:-
1. No family is without a child.
2. Every girl has at least one brother and sister.
Ans: c > a > b > g > f; 9 6 5 4 3.
5. There are 4 boys – Anand, Anandya, Madan and Murali with nic-names perich, zomie, drummy and madeena not in the same order. Some conditions.
Ans: Anand : Perich
Anandya : Drummy
Madan : Zombie
Murali : Madeena
6. There are 3 piles each contains 10, 15, & 20 stones. There are A, B, C, D, F, G and H persons. One man can catch upto four stones from any pile. The last man who takes will win. If first A starts next B and so on, who will win?
Ans: May be F.
7. A clock showing 6 o’clock takes 30 secs to strike 6 times. How long will it take to strike 12 at midnight?
Ans: 66 seconds.
8. Only boy’s aged > 16 wear coats. Boys aged > 15 go to watch football. Some more statements are given. What can be said about those who are watching football?
9. There are 3 societies A, B amp; C having some tractors each. A Gives B and C as many tractors as they already have. After some days B gives A and C as many tractors as they have. After some days C gives A and B as many tractors as they have. Finally each has 24 tractors. What is the original No. of tractors each had in the beginning?
Ans: A – 39. B – 21. C – 12.
10. BE * BE = ACB.
A, B, C, E are non zero numbers. Find B, E.
Ans: B=1 E=9.
11. A person went to a shop and asked for change for 1.15 paise, but he said that he could not only give change for one rupee but also for 50p, 25p, 10p and 5p. What were the coins he had?
Ans: 1–>50p 4—>10p 1—>25p.
12. A man covered 28 steps in 30 seconds but he decided to move fast and covered 34 steps in 18 seconds. How many steps are there on the escalator when stationary?
1. Person1: Most of us are satch J.
Person2: Most of us are jute S.
Person3: Two of us are satch J.
Person4: Three of us are jute J.
Person5: I am satch J we have to find who satch is and who jute is.
Ans: S: Satch J:Jute.
2. Four persons are there to cross a bridge they have one torch light.
Person A can cross in 1 min.
Person B can cross in 2 min.
Person C can cross in 5 min.
Person D can cross in 10 min.
They have to cross bridge with in 17 min. At a time only two persons can cross.
I. A & B —-> 2.
II. A <—- 1.
III. C & D —-> 10.
IV. B <—- 2.
V A & B —-> 2
13. What is the maximum number of slices can you obtain by cutting a cake with only 4 cuts?
14. There are three boxes. In first box, two white balls. In second box, 2 black balls. In third box, 1 white & 1 black ball. The labels on the boxes are not correct. Then you have to open one box and to find the colour of the balls in all boxes.
Ans: Open the box labled black & white. If white balls are there then the box labled with white balls contain black balls and labled with black balls contain one black and one white ball and vice versa, if two black balls are there.
15. Geoffrey, Hallmann and Molly attend and interview and give three different statements each.
To make it a little complex. Out of the three statements made by each one, one is false.
Geoffrey says: I am 22 – false
Hallmann is elder than me by one year.
Molly is 25
Hallmann says: I am not the youngest –
Geoffrey is 2 years younger than me
Molly is younger than me by one year – false
Molly says: Geoffrey is 23
I am a year younger than Geoffrey
(I don’t remember this statement but it is false.)
Goeffrey is 22 as Goef states,
And Goef== 23 as Molly states.
Both cannot be true.
Either one has to be true or either one has to be false.
Start deriving from this point and u get,
Geoffrey Hallmann Molly
Age: 23 25 22
16. The time taken to travel in train from Town A to Town B is 5 hours.
There are trains starting from both towns at an interval of 1 hour.
How many trains meet in 1 trip?
Ans : 10 trains check it as trains come from both sides every hour.
17. Shadow went to an Isle where the natives lie and the visitors speak truth.
Shadow saw a salesman and wanted to know whether he was a native or a visitor.
He did not pose a question directly but asked him indirect instead.
Shadow saw a woman and asked the salesman, “Is that a NATIVE or
VISITOR?” .For which the salesman replied,” She is a visitor”.
Is the salesman a Native or a Visitor?
Since Shadow himself saw him/her as a woman and asked the salesman.
The Salesman replied ,”SHE ” by which he speaks truth and is a Visitor.
Salesman is a Visitor.
18. Three friends divided some bullets equally.
After all of them shot 4 bullets the total number of bullets remaining is equal to the bullets each had after division. Find the original number divided.
Ans: 18 (2 marks)
Initially . x x x
Now x-4 x-4 x-4
Equation is 3x-12 = x
19. There are 3 societies A, B, C.
A lent cars to B and C as many as they had already.
After some time B gave as many tractors to A and C as many as they have.
After sometime c did the same thing. At the end of this transaction each one of them had 24.
Find the cars each originally had.
Ans: A had 39 cars, B had 21 cars & C had 12 cars
20. The Bulls, Pacers, Lakers and Jazz ran for a contest.
Anup, Sujit, John made the following statements regarding results.
Anup said either Bulls or Jazz will definitely win
Sujit said he is confident that Bulls will not win
John said he is confident that neither Jazz nor Lakers will win
When the result came it was found that only one of the above three had made a correct statement.
Who has made the correct statement and who has won the contest.
Ans: Sujith; Lakers
21. Five people A ,B ,C ,D ,E are related to each other.
Four of them make one true statement each as follows.
(i) B is my father’s brother.
(ii) E is my mother-in-law.
(iii)C is my son-in-law’s brother
(iv)A is my brother’s wife.
Ans: (i) D (ii) B (iii) E (iv) C
22. Fifty minutes ago if it was four times as many minutes past three o’clock, how many minutes is it to six o’clock?
Ans: Twenty six minutes.
23. A hotel has 10 stores. Which floor is above the floor below the floor, below the floor above the floor, below the floor above the fifth.
Ans: The sixth floor.
24. Seven members sat around a table for three days for a conference.
The member’s names were Abhishek, Amol, Ankur, Anurag, Bhuwan, Vasu and Vikram.
The meetings were chaired by Vikram.
On the first evening members sat around the table alphabetically.
On the following two nights, Vikram arranged the seating’s so that he could have Abhishek as near to him as possible and absent minded Vasu as far away as he could.
On no evening did any person have sitting next to him a person who had previously been his neighbour. How did Vikram manage to seat everybody to the best advantage on the second and third evenings?
Second evening: Vikram, Ankur, Abhishek, Amol, Vasu, Anurag and Bhuwan.
Third evening :Vikram, Anurag, Abhishek, Vasu, Bhuwan, Ankur, Amol.
25. Two trains start from stations A and B spaced 50 kms apart at the same time and speed.
As the trains start, a bird flies from one train towards the other and on reaching the second train, it flies back to the
first train. This is repeated till the trains collide.
If the speed of the trains is 25 km/h and that of the bird is 100km/h.
How much did the bird travel till the collision.
Ans: 100 kms.
26. Four prisoners escape from a prison.
The prisoners, Mr East, Mr West, Mr South, Mr North head towards different directions after escaping. The following information of their escape was supplied:
The escape routes were The North Road, South Road, East Road and West Road.
None of the prisoners took the road which was their namesake.
Mr. East did not take the South Road
Mr. West did not the South Road.
The West Road was not taken by Mr. East
What road did each of the prisoners take to make their escape?
Ans: Mr. East took the North Road
Mr. West took the East Road
Mr. North took the South Road
Mr. South took the West Road.
27. Complete the series:
5, 20, 24, 6, 2, 8, ?
Ans: 12 (as 5*4=20, 20+4=24, 24/4=6, 6-4=2, 2*4=8, 8+4=12).
28. A soldier loses his way in a thick jungle. At random he walks from his camp but mathematically in an interesting fashion. First he walks one mile East then half mile to North. Then 1/4 mile to West, then 1/8 mile to South and so on making a loop.
Finally how far he is from his camp and in which direction.
Ans: Distance travelled in north and south directions
1/2 – 1/8 + 1/32 – 1/128 + 1/512 – and so on
Similarly in east and west directions
1- 1/4 + 1/16 – 1/64 + 1/256 – and so on
= 1/(( 1- ( – 1/4))
Add both the answers
29. How can 1000000000 be written as a product of two factors neither of them containing zeros
Ans: 2 power 9 x 5 power 9
30. Conversation between two mathematicians:
First : I have three children. The product of their ages is 36.
If you sum their ages, it is exactly same as my neighbour’s door number on my left.
The second mathematician verifies the door number and says that it is not sufficient.
Then the first says ” Ok one more clue is that my youngest is really the youngest”. Immediately the second mathematician answers . Can you answer the question asked by the first mathematician?
What are the children ages?
Ans 1,6 and 6
31. Light glows for every 13 seconds . How many times did it glow between 1:57:58 and 3:20:47 am.
Ans : 383 + 1 = 384
32. 500 men are arranged in an array of 10 rows and 50 columns according to their heights.
Tallest among each row of all are asked to fall out.
And the shortest among them is A.
Similarly after resuming that to their original positions that the shortest among each column are asked to fall out.
And the tallest among them is B .
Now who is taller among A and B ?
33. A person with some money spends1/3 for cloths, 1/5 of the remaining for food and 1/4 of the remaining for travel.
He is left with Rs 100/- . How much did he have with him in the beginning ?
Ans: Rs 250/-
34. There are six boxes containing 5 , 7 , 14 , 16 , 18 , 29 balls of either red or blue in colour.
Some boxes contain only red balls and others contain only blue. One sales man sold one box
out of them and then he says ” I have the same number of red balls left out as that of blue “.
Which box is the one he sold out ?
Ans: Total no of balls = 89 and (89-29 /2) = 60/2 = 30
and also 14 + 16 = 5 + 7 + 18 = 30
35. Grass in lawn grows equally thick and in a uniform rate.
It takes 24 days for 70 cows and 60 days for 30 cows to eat the whole of the grass.
How many cows are needed to eat the grass in 96 days.?
Ans : 20
g – grass at the beginning
r – rate at which grass grows, per day
y – rate at which one cow eats grass, per day
n – no of cows to eat the grass in 96 days
g + 24*r = 70 * 24 * y
g + 60*r = 30 * 60 * y
g + 96*r = n * 96 * y
Solving, n = 20.