There are five sheets of paper each of which has a whole number on one side and and an alphabet on the other side written on it as shown below.

What is the minimum number of sheets that is necessary and sufficient that you will turn over to verify whether the proposition given below about them is true or false? What are the sheets that you will turn over?

Proposition: “If there is a prime number on one side of a sheet then the other side of the sheet has a vowel.”

**Answer:**

Two: Sheets 1 and 2.

**Solution:**

Sheet 1 has to be turned over to verify the truth of the proposition. If it doesn’t contain a vowel on the other side, then the proposition can be declared as false. This will verify the statement to be true.

Sheet 2 has also to be turned over. If it has got a prime number on the other side then it will disprove the proposition. This will verify the statement to generally true for all cases by the help of contradiction.

One does not need to turn over sheet 4 because the proposition doesn’t imply that only those sheets with a prime number on one side have got a vowel on the other.

Sheets 3 and 5 are of no help to disprove or prove the proposition obviously.

## Recommended Posts:

- Minimum swaps to group similar characters side by side?
- How to place two div side-by-side of the same height using CSS?
- Python program to check if given string is vowel Palindrome
- Check if a number has prime count of divisors
- Puzzle | Minimum colors required to color a chessboard with no two given pair threatening each other
- Puzzle 15 | (Camel and Banana Puzzle)
- Puzzle 24 | (10 Coins Puzzle)
- Puzzle 27 | (Hourglasses Puzzle)
- Puzzle 28 | (Newspaper Puzzle)
- Puzzle 29 | (Car Wheel Puzzle)
- Puzzle 31 | (Minimum cut Puzzle)
- Puzzle 33 | ( Rs 500 Note Puzzle )
- Puzzle 34 | (Prisoner and Policeman Puzzle)
- Puzzle 36 | (Matchstick Puzzle)
- Puzzle 38 | (Tic Tac Toe Puzzle)
- Puzzle 39 | (100 coins puzzle)
- Puzzle 51| Cheryl’s Birthday Puzzle and Solution
- Puzzle 81 | 100 people in a circle with gun puzzle
- Puzzle 85 | Chain Link Puzzle
- Puzzle | Elevator Puzzle

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.