Susan and Lisa decided to play tennis against each other. They bet $1 on each game they played. Susan won three bets and Lisa won $5. How many games did they play?
They played eleven games.
Lisa lost three games so she had to win three additional games to break even. Then she had to win five more games to win $5. Therefore, the total number of games is the sum of three and three and five.
Why this works
This riddle plays with the concepts of winning, losing, and the net gain in bets. Susan won three games, which means Lisa lost $3 right off the bat. To break even, Lisa needed to win those three games back, and then she needed to win an additional five games to end up with a $5 profit. So, the calculation goes: 3 games lost (by Lisa) + 3 games won (to break even) + 5 games won (for profit) equals a total of 11 games played. It's a clever breakdown of how wins and losses accumulate in betting!