100 coins puzzle | Puzzles for Interview - Interview Preparation PDF Download

Introduction

The 100 coins puzzle is a popular mathematical puzzle that challenges your logical thinking and problem-solving skills. In this puzzle, you have to split 100 coins into two piles such that there are the same number of heads up in each pile. Sounds easy? Let's dive into the solution.

Solution

To solve the puzzle, follow these steps:
Step 1: Divide the coins into two piles. Let's say pile one has 'h' no. of heads and 't' no. of tails, while the other pile will have '10-h' heads and '90-t' tails.
Step 2: Flip all the coins in one pile. Let's say we flip coins of pile two. Now, the number of heads and tails in that pile will interchange. The pile will have '90-t' heads and '10-h' tails.
Step 3: Compare the number of heads in both piles. We know that the number of heads in pile one is 'h', and in pile two, it is '90-t.'
Step 4: Equate the number of heads in both piles. Since we flipped the coins in pile two, the number of heads in pile one will be the same as the number of heads in pile two. So, we can equate the two and get the equation 'h=90-t.'
Step 5: Solve the equation. We have one equation and one variable. We can substitute the value of 'h' from the equation 'h=90-t' into the equation 'h+t=90.'
Step 6: Split the coins into two piles. We get 't=45' and 'h=45.' Therefore, we can split the coins into two piles, one with 45 heads and 55 tails, and the other with 55 heads and 45 tails.

Conclusion

The solution to the 100 coins puzzle is quite simple. By dividing the coins into two piles, flipping the coins in one pile, and equating the number of heads in both piles, we can get the solution. The key is to think logically and approach the problem step-by-step.