# Ericsson Interview Puzzle With Answer

Posted on :24-02-2016
Ericsson Interview Puzzle:-

Q1. A ship went on a voyage after 180 miles a plane started with 10 times speed that of the ship. Find the distance when they meet from starting point.

ANS: 200 miles.

Explanation:

180 + (x/10) = x
x = 20
180+20=200miles.

Q2. Light glows for every 13 seconds. How many times did it between 1:57:58 and 3:20:47 am?

ANS: 383 + 1 = 384

Q3. Three friends divided some bullets equally. After all of them shot 4 bullets the total number of remaining bullets is equal to that of one has after division. Find the original number divided.

ANS: 18 2

Explanation:

x x x
x-4 x-4 x-4
3x-12 = x
x= 6
so answer is 18 2 marks.

Q4. A person spending out 1/3 for cloths, 1/5 of the remaining for food and 1/4 of the remaining for travelled is left with Rs 100/- . How he had in the beginning?

ANS: RS 250/-

Q5. In a tournament there are 20 flag poles equidistant from each other. Each runner starts from the first flag. In 24 sec the runner reaches the 12th flag. How much it will take him to complete the 20th flag?

ANS: (24/11)*19

Q6. 1000000000 can be written as a product of two factors neither of them containing zeros.

ANS: 2 power 9 x 5 power 9

Q7. You have 5 jars of pills. Each pill weighs 10 gram, except for contaminated pills contained in one jar, where each pill weighs 9 gm. Given a scale, how could you tell which jar had the contaminated pills in just one measurement?

ANS: 1. Mark the jars with numbers 1, 2, 3, 4, and 5.
2. Take 1 pill from jar 1, take 2 pills from jar 2, take 3 pills from jar 3, take 4 pills from jar 4 and take 5 pills from jar 5.
3. Put all of them on the scale at once and take the measurement.
4. Now, subtract the measurement from 150 ( 1*10 + 2*10 + 3*10 + 4*10 + 5*10)
5. The result will give you the jar number which has contaminated pill.

Q8. At 6 -o clock, clock ticks 6 times. The time between first and last ticks was 30 sec. How much time it takes at 12 -o clock?

ANS: 66 sec

Q9. A beggar collects cigarette stubs and makes one full cigarette with every 7 stubs. Once he gets 49 stubs. How many cigarettes can he smoke totally?

ANS: 8

Q10. There N stations on a railroad. After adding x stations 46 additional tickets have to be printed. Find N and X.

ANS: let N(N-1) = t;
(N+x)(N+x-1) = t+46;
trail and error method x=2 and N=11.

Q11. You have to draw 3 concentric circles with a line passing through 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.

Q12. Given a rectangular (cuboidal for the puritans) cake with a rectangular piece removed (any size or orientation), how would you cut the remainder of the cake into two equal halves with one straight cut of a knife?

ANS: Join the centers of the original and the removed rectangle. It works for cuboids too! BTW, I have been getting many questions asking why a horizontal slice across the middle will not do. Please note the any size or orientation in the question! Do not get boxed in by the way you cut your birthday cake. Think out of the box.

Q13. 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.

Q14. 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)

Q15. 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.

Q16. In a race, you drove 1st lap with 40 kmph and in the second lap at what speed you must drive so that your average speed must be 80 kmph.

ANS: Its impossible! If you drove the first lap in 40 kmph, its impossible that the average speed of both the laps is 80 kmph.
for eg. consider one lap distance = 80 km.
time req. to cover 1 lap = 80 km/40 kmph = 2 hrs.
If the avg. speed is 80 kmph, then the total time would have taken = 160 kms/80 kmph = 2 hrs.
Same is the case with any other distance you consider. So the average to be 80 kmph is impossible.

Q17. If a bear walks one mile south, turns left and walks one mile to the east and then turns left again and walks one mile north and arrives at its original position, what is the color of the bear.

ANS: The color of the bear is trivial. The possible solutions to it are interesting. In addition to the trivial north pole, there are additional circles near south pole.

Q18. You are given a cake; one of its corner is broken. How will you cut the rest into two equal parts?

ANS: Slice the cake

Q19. 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)

Q20. 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 you are 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)

Q21. You are a landscape designer and your boss asked you 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 it is possible

Q22. If one tyre of a car suddenly gets stolen and after sometime u find the tyre without the screws how will you make your journey complete?

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

Q23. 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.

Q24. What is the height of room if after entering the room with a watch your 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 your height to get the height of the room.

Q25. How can you measure a room height using a thermometer?

ANS: Temp varies with height. But its dependent on various other factors like humidity, wind etc.

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