Posts
Check out these tricky math riddles.
"You might want to break out a calculator because it takes a genius to solve these tricky math riddles" according to Morgan Cutolo, Author at Reader's Digest.
Knight moves
 |
| Photo: |
I have a calculator that can display ten digits. How many different ten-digit numbers can I type using just the 0-9 keys once each, and moving from one keypress to the next using the knight's move in chess? (In chess, the knight move in an L-shape — one square up and two across, two squares down and one across, two squares up and one across, and other like combinations)
Answer: You can form the numbers 5034927618 and 5038167294. You can also form their reverses: 8167294305 and 4927618305. Hence four different numbers can be made. The key point is to realize that the number must start or end on the '5' key, followed/preceded by the '0' key, otherwise, there is no way of using all ten keys during the route. Only 2 percent of people can solve Einstein's Riddle. Can you?
Read more...
Source: Reader's Digest
