<span style="color:red">The World's 200 Hardest Brain Teasers Mind-Boggling Puzzles, Problems, and Curious Questions to Sharpen Your Brain</span>
Gary Gruber, "The World's 200 Hardest Brain Teasers: Mind-Boggling Puzzles, Problems, and Curious Questions to Sharpen Your Brain"
2010 | ISBN-10: 1402238576 | PDF | 208 pages | 3 MB
FLEX YOUR brain power like never before!
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...