#### Topic: Puzzles asked in interviews

The puzzles below were asked during my interview with different companies:

1. I have 3 consecutive numbers greater than 5. The first and third numbers are prime numbers. Prove that middle number is multiple of 6.

2. You have a 7 kg gold bar (think like it is a kit-kat bar of 1 kgs joined together). How would you pay a worker each day for seven days from a gold bar if you can only break the bar twice. The worker's wage is 1kg gold per day?

3. You are given two candles of equal size. Each candle can burn for 1hr. How will you measure a) 30 min and b) 45 mins with these candles. Note you cannot cut the candles.

4. You have 12 balls out of which 1 is of different weight and the rest have same weight. You are also given a weighing balance. How will you identify the ball which differs in weight in 3 weighings?

5. There are 3 boxes of 2 balls each. One box contains 2 black balls, another contains 2 white balls and the 3rd box contains a black and a white ball. Each box is labelled incorrectly regarding its contents. You are allowed to choose one box randomly and pick only one ball from it and see its color. The other ball cannot be seen. a) How will you mark the box labels correctly? b) A more tough one will be how many such operations (picking a box and then picking a ball) are required to correctly identify the boxes.

Let us discuss and solve these