# Mathematical Puzzles

## 3 and 5 litre water Jug to measure 4 litres interview puzzle

PUZZLE: You have a 3 litre jag and a 5 litre water jug. Jug does not have any marking. You have plenty of water or running tap. How would you measure 4 litres of water? Note that except 3 and 5 litre jug you don’t have any container or jug but only 3 and 5 […]

## Pair of Socks puzzle – Number of socks to pick for matching pair

Pair of Socks puzzle: You have 100 black socks and 100 white socks mixed up in a drawer. You must pick socks blindly from the drawer. How many socks you need to take out to be sure of having a matching pair? Note that question does not ask for specific color socks but just a […]

## Burning ropes puzzle to measure time

Burning ropes Puzzle: You have two ropes and a lighter. Each rope takes exactly 60 minutes to burn completely. Given ropes burn inconsistently (for example, if you light it at one end, the first half of the rope may burn in 5 minutes while the second half may take 55 minutes). how do you measure […]

## Number of Handshakes interview puzzle with formula

Interview puzzle: If you have 20 people in a party and each shakes everyone else’s hand only once, how many handshakes take place? Use the below formula to get answer quickly. Formula: N*(N-1)/2 If we put N=20, then answer will be 190. Let’s understand the formula. If there are n people at the party, then […]

## Bridge crossing with torch interview puzzle

Interview Puzzle: There are four persons A, B, C and D who wants to cross a weak bridge in the night. They have one torch with them. Persons A, B, C and D takes 1,2,5 and 8 minutes respectively to cross the complete bridge. At a time, only 2 persons can walk on the bridge. […]

## 3 Jugs interview puzzle – 12, 8 and 5 liter Jug

PUZZLE: You have three jugs. They can hold 12 liters, 8 liters, and 5 liters of milk or say water respectively. 12-liter jug is full of milk, but you need to split it in half using only the jugs on hand. How can you split up the water to give away exactly 6 liter, and […]

## find angle between the hands of a clock at 5:15 by Clock Angle Formula

Interview PUZZLE: How many degrees are in the angle between the hour and minute hands of a clock when the time is quarter past 5 i.e. 5:15? Solution: We will use simple clock angle formula to solve this problems. First let’s find how many degrees are in 1 minute of the clock. Since, minute hand, […]

## A snail is climbing out of a well – Interview Puzzle

Snail climbing out of a well – Mathematical interview puzzle – A snail is at the bottom of a 30 foot well. Every hour the snail is able to climb up 3 feet and then it slides back down 2 feet. How many hours does it take for the snail to get out of the […]

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