Honest Man and single Question
Posted on May 10, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem An honest man holds a card with one of the three possible numbers on it “1”, “2” or “3”. You can ask one question and the man allowed to answer only “Yes”,”No” and “I don’t know”. The honest man obviously never lies. Which question would you ask to say with 100% certainty which number is on the card the honest man holds?
Solution Question should be: “If I substract 2 from your number, and then take squery root, would the result be greater than zero?
[Read More]Elephant and Bananas
Posted on May 10, 2014
(Last modified on August 7, 2020)
| 5 minutes
| Kinshuk Chandra
Problem There are 2 cities A and B, 1000 Kms apart. We have 3000 bananas in city A and a elephant, which can carry max 1000 bananas at any given time. The elephant needs to eat a banana every 1 Km.
How many maximum number of bananas can be transferred to city B?
Note: The elephant cannot go without bananas.
Generalized Question:
There are 2 cities A and B, ‘D’ Km apart.
[Read More]Why does mirror lies sometimes?
Posted on May 9, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem Imagine you are standing in front of a mirror, facing it. Raise your left hand. Raise your right hand. Look at your reflection. When you raise your left hand your reflection raises what appears to be his right hand. But when you tilt your head up, your reflection does too, and does not appear to tilt his/her head down. Why is it that the mirror appears to reverse left and right, but not up and down?
[Read More]Average salary of n people in the room
Posted on May 7, 2014
(Last modified on August 7, 2020)
| 2 minutes
| Kinshuk Chandra
Question:
How can n people know the average of their salaries without disclosing their own salaries to each other?
Solution:
Let’s say salaries of n people (P1, P2, P3…..Pn) are S1, S2, S3…..Sn respectively. To know the average of the salary i.e. (S1 + S2 + S3 + ….. + Sn) / n, they will follow the following steps -
P1 adds a random amount, say R1 to his own salary and gives that to P2 (P2 won’t be able to know P1’s salary as he has added a random amount known to him only).
[Read More]Fit 1*2 dominos in 2*N strip
Posted on May 2, 2014
(Last modified on August 7, 2020)
| 2 minutes
| Kinshuk Chandra
Problem In how many ways can one tile a 2 X N strip of square cells with 1 X 2 dominos?
Solution Please notice that we can put tiles either vertically or horizontally. For putting vertical tiles, we need a gap of at least 2 X 2. For putting horizontal tiles, we need a gap of 2 X 1. Number of arrangements will be the same as the arrangements, we can make with gaps of 1 and 2 (order dependent).
[Read More]Stone thrown from the boat
Posted on April 11, 2014
(Last modified on August 7, 2020)
| 2 minutes
| Kinshuk Chandra
Problem Will there be any change in water level/height of floating part of the boat if stones are dropped into the pond from a floating boat?
Follow up - What if you are given empty 2L bottle and chained under the boat?
Solution There is maybe a little physics needed here…
When an object is floating be it because it is something less dense than water, say polystyrene, or because it is in a boat, say a brick and the whole boat is less dense than water, then it displaces in the water it’s own mass.
[Read More]Three children
Posted on April 11, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem :
Tom’s mother has three children. One is named April, one is named May. What is the third one named?
Solution :
Tom
Black Dog, Black-out and Driver Problem
Posted on April 11, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem : A completely black dog was strolling down Main Street during a total blackout affecting the entire town. Not a single streetlight had been on for hours. Just as the dog was crossing the middle line a Buick Skylark with 2 broken headlights speedily approaches his position, but manages to swerve out of the way just in time. How could the driver have possibly seen the dog to swerve in time?
[Read More]Inhereting wealth from wise Sheikh
Posted on April 11, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem : An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower will win. The brothers, after wandering aimlessly for days, ask a wise man for advise. After hearing the advice they jump on the camels and race as fast as they can to the city. What does the wise man say?
[Read More]Book worm
Posted on April 11, 2014
(Last modified on August 7, 2020)
| 1 minutes
| Kinshuk Chandra
Problem : A bookworm eats from the first page of an encyclopedia to the last page. The bookworm eats in a straight line. The encyclopedia consists of ten 1000-page volumes and is sitting on a bookshelf in the usual order. Not counting covers, title pages, etc., how many pages does the bookworm eat through?
Solution : On a book shelf the first page of the first volume is on the “inside”
[Read More]