The Worlds 200 Hardest brain teasers mind boggling puzzles problem
About the Book
From acclaimed author Dr. Gary Gruber, whose proven critical-thinking methods have sold more than seven million books, this collection of mind-bending brain teasers is sure to challenge even the most experienced problem solver. Inside are logic puzzles, riddles, maddening math problems, mental games, and more!
A ship is twice as old as the ship’s boiler was when the ship was as old as the boiler is. The ratio of the boiler’s age now to the ship’s age now is what?
What English word contains all the vowels, in alphabetical order?
What is the three-digit number that can be made from the digits 2, 3, 5, and 7 where no two digits in the three-digit number are alike, and where the three-digit number is a multiple of each of the digits chosen?