A dysfunctional family has to cross the river. On one side of the river are a mom and 2 daughters, dad and 2 sons, the maid and the dog. There is a boat only big enough to hold 2 people (counting the dog as 1 person). Only the adults are capable of … [Continue reading]

## Defective coins

We have 10 bags of 1 Rupee coins. One bag contains all the defective coins, the weight of each coin in that bag is 1 gram lesser than the weight of a normal 1 Rupee coin. You have a spring balance, which tells the exact weight. After how many minimum … [Continue reading]

## Hats and IIT students

Nine IITians were sitting in a classroom. Their prof wanted to test them. One day he told all of his 9 students that he has 9 hats, colored either in red or black. He also added that he has at least one hat with red color and the no. of black hats is … [Continue reading]

## Heavier ball

You have 8 balls all look identical (in shape, color etc.). All of them have same weight except one defective ball which is heavier than others. You can use a two sided balance system (not the electronic one). Find the minimum no. of measures … [Continue reading]

## Defective ball

You have 12 balls all look identical (in shape, color etc.). All of them have same weight except one defective ball. You don't know that the defective one is heavier or lighter than other balls. You can use a two sided balance system (not the … [Continue reading]

## River crossing

Three cannibals and three anthropologists have to cross a river. The boat they have is only big enough for two people. If at any point in time there are more cannibals on one side of the river than anthropologists, the cannibals will eat them. What … [Continue reading]

## King and wine bottles

A bad king has a cellar of 1000 bottles of delightful and very expensive wine. A neighboring queen plots to kill the bad king and sends a servant to poison the wine. Fortunately (or say unfortunately) the bad king's guards catch the servant after he … [Continue reading]

## Wires on fire

A guy has two wires of varying thickness, which each burns in 60 minutes. He actually wants to measure 45 mins. How can he measure 45 mins using only these two wires. (he can't cut the one wire in half because the wires are non-homogeneous and he … [Continue reading]

## Jelly beans

You have three jars that are all mislabeled. One contains peanut butter jelly beans, another grape jelly jelly beans and the third has a mix of both (not necessarily half-half mix). How many jelly beans would you have to pull out and out of which … [Continue reading]

## Bridge

Four people are on this side of the bridge. The bridge will be destroyed by a bomb in 17 minutes. Everyone has to get across before that. Problem is that it's dark and so you can't cross the bridge without a flashlight and they only have one … [Continue reading]