The sum of Janos' age and David's age is 34 years. Five years ago the sum of twice Janos' age and three times David's age was 61 years. What are their present age?
Because if you divide 34 by 2 you get 17. Then subtract 17 minus 5 which equals 12 so you multiply 12 times 2 for Janos' age and 12 times 3 for David's age which makes 60 but not 61. Their present age is 17.