Are you among the top 15% of brainiacs in the country who can solve this math problem? Brainteasers and puzzles are an excellent way to keep your mind as healthy as the rest of your body. They can ...

She’s right—using simultaneous equations does get really complicated, and if you’d like to send me your work for the solution, I’d love to see it. But the system is also kind of a trick. Like a sudoku ...