Infosys Placement Papers 29
1. A begger collects cigarette stubs and makes one ful cigarette with every 7 stubs. Once he gets 49 stubs . How many cigarettes can he smoke totally?
2. A soldier loses his way in a thick jungle at random 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: In north and south directions
1/2 - 1/8 + 1/32 - 1/128 + 1/512 - and so on = 1/2/((1-(-1/4)) similarly in
east and west directions 1- 1/4 + 1/16 - 1/64 + 1/256 - and so on = 1/(( 1-
( - 1/4)).
3. How 1000000000 can be written as a product of two factors neither of them containing zeros?
Ans: 2 power 9 x 5 ppower 9 (check the answer).
4. Conversation between two mathematcians:
First : I have three childern. 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 verfies the door number and says that the clue is not sufficient. Then the first says " OK, one more clue is that my youngest is the youngest". Immmediately the second mathematician answers. Can you answer the question asked by the first mathematician? What are the childeren ages?
Ans: 2 and 3 and 6.
5. Light glows for every 13 seconds. How many times did it between 1:57:58 and 3:20:47 AM?
Ans: 383 + 1 = 384.
6. 500 men are arranged in an array of 10 rows and 50 columns. ALL tallest among each row are asked to fall out. And the shortest among them is A. Similarly after resuming that to their originaal positions that the shortest among each column are asked to fall out. And the longest among them is B. Now who is taller among A and B?
7. A person spending out 1/3 for cloths, 1/5 of the remaining for food and 1/4 of the remaining for travelles. He is left with Rs 100/-. How he had in the begining?
Ans: Rs 250/-.
8. 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 solds out?
Ans: Total no of balls = 89 and (89-29 /2 = 60/2 = 30 and also 14 + 16 = 5 + 7 + 18 = 30.
9. A chain is broken into three pieces of equal lengths, containing 3 links each. It is taken to a blacksmith to join into a single continuous one. How many minimum number of links are to to be opened to make it?
10. Grass in lawn grows equally thick and in a uniform rate. It takes 24 days for 70 cows and 60 for 30 cows. How many cows can eat away the same in 96 days?
Ans: 18 or 19.
11. There is a certain four digit number whose fourth digit is twice the first digit. Third digit is three more than second digit. Sum of the first and fourth digits twice the third number. What was that number?
Ans: 2034 and 4368.