Puzzling Puzzles

1
Puzzling Puzzles

•   Ann, a very competitive person, decides to give
  herself 2 points for every crossword puzzle in
  her daily newspaper that she completes correctly
  and to forfeit 3 points for every crossword in
  the paper that she completes incorrectly or
  cannot complete.
• After 30 days of working the puzzles, Ann has a
  score of zero. How many puzzles has she solved
  correctly?

2

• Solution
• Let a the number she gets correct
• Let b the number she gets wrong
• 2a 3b
• a b 30
• a 18 b 12