Infosys Sample Puzzles

7 questions
1) Eight friends Harsha, Fakis, Balaji, Eswar, Dhinesh, Chandra, Geetha, and Ahmed are
sitting in a circle facing the center.
Balaji is sitting between Geetha and Dhinesh. Harsha is third to the left of Balaji and
second to the right of Ahmed. Chandra is sitting between Ahmed and Geetha and Balaji
and Eshwar are not sitting opposite to each other. Who is third to the left of Dhinesh?
Answer: Fakis
Explanation: Arranging the friends as per the question statement we can arrive at the following
diagram
Ahmed
Fakis Chandra
Harsha Geetha
Eswar Balaji
Dhinesh
Hence correct answer is Fakis.
2) A fast typist can type some matter in 2 hours and a slow typist can type the same in 3
hours. If both type jointly, in how much time will they finish?
Answer: 1 hr 12 min
Explanation : The fast typist's work done in 1 hr = 1/2
The slow typist's work done in 1 hr = 1/3
If they work jointly, work done in 1 hr = 1/2+1/3 = 5/6
So, the work will be completed in 6/5 hours. i.e., 1+1/5 hours = 1hr 12 min
3) Today is 4.11.09. Keeping that figure 41109 in mind, i have arrived at the following
sequence: 2, 1, 9, 5, _ Which of the following four numbers can fill the dash?
Options
a) 7
b) 65
c) 4563
d) 262145
Answer : 41109
1^4 + 1 = 2
1^1 + 0 = 1
0^1 + 9 = 9
9^0 + 4 = 5
So next is 4^9 + 1 = 262145
4) Let S be a Set of some positive integral numbers; with an average of 47; and containing
the number 83. The numbers may or may not be distinct .However ; when the number 83 is
removed ; the Avg drops to 46 .What is the largest number that can be possibly contained
in that Set ?
Solution:
Let S be the sum of that set of n positive integers. S/n = 47
(S - 83)/(n - 1) = 46
Solving the above 2 equations, we get S = 1739; n = 37.
This set of 37 positive integers contains 83. To get to the expected answer, we have to
Suppose that 35 of the remaining 36 integers has a value of 1 each (least +ve integer).
Thus, the largest possible integer in the set = 1739 - 83 - 35*1 = 1621
5) Sum of squares of two numbers 'x' and 'y' is less than or equal to 100. How many sets
of integer solutions of 'x', 'y' is possible?
Answer: Total 317 solutions
Explanation:
x = 0, |y| <= 10 -> 21 solutions
|x| = 1, |y| <= 9 -> 38 solutions
|x| = 2, |y| <= 9 -> 38 solutions
|x| = 3, |y| <= 9 -> 38 solutions
|x| = 4, |y| <= 9 -> 38 solutions
|x| = 5, |y| <= 8 -> 34 solutions
|x| = 6, |y| <= 8 -> 34 solutions
|x| = 7, |y| <= 7 -> 30 solutions
|x| = 8, |y| <= 6 -> 26 solutions
|x| = 9, |y| <= 4 -> 18 solutions
|x| = 10, y = 0 -> 2 solutions
6) There is a unique number of which the square and the cube together use all ciphers
from 0 up to 9 exactly once. Which number is this?
Answer: The number is 69.
Explanation:
69^2=4761 and 69^3=328509..
7) You are standing next to a well, and you have two jugs. One jug has a content of 3
litres and the other one has a content of 5 litres. How can you get just 4 litres of water
using only these two jugs?
Solution:
Fill 3 litre jug pour to 5 litre jug
Fill again 3 litre jug and add to 5 litre jug then 1 litre will be there in 3 litre jug
Pour all water outside from 5 litre jug
Fill 1 litre water from 3 litre jug to 5 litre jug
Fill 3 litre jug and add to 5 litre jug making it 4 litres of water.

Posted in: Infosys, Placement Papers