Infosys Puzzle

1. You are given two candles of equal size, which can burn 1 hour each. You have

to measure 90 minutes with these candles. (There is no scale or clock). Also u r

given a lighter.

Ans: 1. First light up the two ends of the 1st candle. When it will burn out light up

one end of the second candle. (30+60=90)

2. Try the similar problem to measure 45 minutes.

Ans: First light-up the two ends of the 1st candle and one end of the 2nd candle.

When the 1st candle will burn out ,then light up the both ends of the 2nd candle

(15+30=45)

3. You r given a thermometer. What can u do by this without measuring the

temperature?

Ans: if u put thermometer into a tree it won't grow anymore, will just die off

4. How it is possible to place four points that are equidistance from each other?

OR

U r a landscape designer and your boss asked u to design a landscape such

that you should place 4 trees equidistance from each other.

(Distance from each tree to the other must be same)

Ans: Only 3 points can be equidistant from each other. But if u place points in the

shape of a pyramid then its possible

5. You are given a cake; one of its corner is broken. How will u cut the rest into

Two equal parts?

Ans: Slice the cake

6. How will you recognize the magnet & magnetic material & non-magnetic material?

Ans: Drag one piece of material over another. There is no attractive force in the

middle portion of the magnet.

OR

Get a piece of thread and tie up with the one bar and check for poles. If it iron bar

then it moves freely and if it is magnetic bar then it fix in one direction according to

poles.

7. If one tyre of a car suddenly gets stolen.... and after sometime u find the tyre

without the screws how will u make ur journey complete?

Ans: Open 3 screws, 1 from each tyre and fix the tyre.

8. How can u measure a room height using a thermometer?

Ans: temp varies with height. but its dependent on various other factors like

humidity, wind etc.

9. What is the height of room if after entering the room with a watch ur head

strikes a hanging bulb?

Ans: Oscillate the hanging bulb. Calculate the time period for one complete

oscillation by Simple Harmonic Motion (SHM) of the handing bulb. Put it in the

formula T=2 * 3.14 * (L/G)^1/2

L will be the length of the hanging thread.

Add the L with ur height to get the height of the room.

OR

Ans: Drop it from the room and find the time at which it strikes the floor. Using

physics formula s = (at^2)/2 (IM NOT SURE ABOUT THIS ONE)

10. Color of bear.... if it falls from 1m height in 1s.

Ans: We get 'g' perfect 10 which is only in poles...hence polar bear...color White

11. How will you measure height of building when you are at the top of the building?

And if you have stone with you.

Ans: Drop the stone and find the time taken for the stone to reach the ground. find

height using the formula

s = a + gt ( s = height, a= initial velocity=0, g=9.8m/s, t = time taken)

12. How wud u catch and receive a ball in same direction? (Dropping is from north

And receiving from bottom not accepted, as it is 2 directions)

Ans: ?

13. 25 statements given. Some tell truth, some false and some alternators. Find out

the true statements.

Ans: ?

14. Can u make 120 with 5 zeros?

Ans: Factorial (factorial (0)+factorial (0)+factorial (0)+factorial (0)+factorial (0)) =

120

15.There are three people A, B, C. Liars are of same type and Truth speaking people

are of same type. Find out who is speaking truth and who is speaking false from the

following statements:

a) A says: B is a liar.

b) B says: A and C are of same type.

Ans: lets assume A is speaking truth. It means B is a liar then it means A and C are

not of same type.

16.5 swimmers A, B, C, E, F and many conditions of their positions like there are

Two b/w A & F, B doesn't win etc the question was to find who was b/w like E & D?

Ans: ?

17. in a race u drove 1st lap with 40kmph and in the second lap at what speed u

must drive so that ur average speed must be 80kmph.

Ans: its impossible! if u drove the first lap in 40 kmph, its impossible that the

average speed of both the laps is 80kmph.

for eg. consider one lap distance = 80km.

time req. to cover 1 lap = 80km/40kmph = 2 hrs.

if the avg. speed is 80kmph, then the total time would have taken =

160kms/80kmph = 2 hrs.

same is the case with any other distance u consider. so the avg to be 80kmph is

impossible

18. You have to draw 3 concentric circles with a line passing thru their center

without lifting hand.

Ans: Start the line complete one circle move inside circles along the line and then

draw second circle. Like wise rest.

19. A rectangular paper is there. At a corner a rectangular size paper is taken from

it. Now you have to cut the remaining paper into two equal halves.

Ans: try it on the paper. You must fold the part that has complete paper and select

Half of it and then fold the part that cut and selects half of it and then cut along

the folding. (I DONT UNDERSTAND THIS ONE!!)

20. Value of (x-a)(x-b)...........(x-z)

Ans: 0 as there's X-X term

21. There are 9 coins. 8 are of 1 gm and 1 is of 2 grams. How will you find out the

heavier coin in minimum number of weighing and how many weighing it will need?

Ans: 2 weighing ( Divide the number of coins into 3 parts at each weighing)