I’m reposting this great puzzle, found originally at The Math Less Traveled blog. Enjoy!
There are five true and five false statements about the secret number. Each pair of statements contains one true and one false statement. Find the trues, find the falses, and find the number.
1a. I have 2 digits
1b. I am even
2a. I contain a “7”
2b. I am prime
3a. I am the product of two consecutive odd integers
3b. I am one more than a perfect square
4a. I am divisible by 11
4b. I am one more than a perfect cube
5a. I am a perfect square
5b. I have 3 digits