hard

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!

Common Wrong Answers

“8”

If they played 8 games, Lisa would have lost 3 and would have needed to win 3 more to break even, resulting in 6 games played. However, she also needs to win 5 additional games to have a net profit, which would require at least 11 games.

“10”

If they played 10 games, Lisa would win only 7 games (because she lost 3), which means she wouldn't have enough wins to end up with a profit of $5 after losing 3 games. Thus, 10 games does not satisfy the conditions of the riddle.

“12”

If they played 12 games, Lisa winning 7 would mean she would actually lose more than she wins, resulting in a net loss rather than the stated profit of $5. The total needs to account for her necessary wins beyond breaking even.

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