Reasoning · Grade 4-2 Leagues and Tournaments

Problem

Fill a bracket from win-loss clues

Mason, Tyler, Owen, Dylan and Grace play a knockout arm-wrestling tournament. “Tyler” is already written in the top box and on the left branch, “Mason” on the right branch, and the bottom row groups the five starting boxes 1, 2 and 2 from the left. Mason and Tyler each played 2 games; Owen beat Dylan and never faced Mason. Fill in every box of the bracket.
Tyler Tyler Mason
Your answer
How to solve
Strategy Eliminate Possibilities — There are only five people and five starting boxes, so the candidate set is small and completely finite — the right tool is to knock out the impossible placements one clue at a time. The key observation, which comes from reading the bracket itself, is that each starting box already decides how many games its player can possibly play. That turns the 'played 2 games' clue into a position clue, which fixes Tyler at once; the other two clues then eliminate the remaining choices for Owen, Dylan and Grace.
1STEP 1

Read off how many games each starting box can give you

Each starting box allows a different game count.

leftmost box: 1 or 2; 2nd/3rd box: 1, 2 or 3; 4th/5th box: 1 or 2
2STEP 2

Tyler must start in the leftmost bottom box

Winning in 2 games puts Tyler in the leftmost box.

champion from a 2nd/3rd box → 3 games ≠ 2
3STEP 3

Mason starts in one of the two rightmost bottom boxes

Mason takes one of the two rightmost boxes.

1 + 1 = 2
4STEP 4

Owen cannot be in the other right-hand box

Owen cannot take the other of those two.

5STEP 5

Dylan takes the other of those two boxes, and Owen wins that game

Owen and Dylan fill the middle pair and Owen wins.

6STEP 6

Grace fills the last box

The last box is Grace.

7STEP 7

List the four games and check all three clues

The four games match all three clues.

Tyler 2, Mason 2, Owen 2, Dylan 1, Grace 1
Answer
Tyler / Owen, Dylan / Mason, Grace
2, 2, 2, 1, 1
The filled bracket is consistent everywhere: five contestants in a knockout tournament must produce exactly 5 − 1 = 4 games, and the list has exactly 4. Each game has one winner and one loser, so the win totals add to 4 — Owen 1, Mason 1, Tyler 2 — and the loss totals also add to 4, one each for Dylan, Owen, Grace and Mason. Every game count is between 1 and 3, as the bracket allows, and the two players said to have played 2 games each, Mason and Tyler, do have exactly 2. Checking every possible filling of the five boxes by machine confirms that only these placements survive all three clues, and that the only freedom left is the two swaps noted in the answer — which is exactly what the answer key says as well.
Takeaway

In a knockout bracket, where you start already decides how many games you can play — so 'how many games' is really a clue about where a name goes.

  • Read off how many games each starting box can give you
  • Tyler must start in the leftmost bottom box
  • Mason starts in one of the two rightmost bottom boxes
  • Owen cannot be in the other right-hand box
  • Dylan takes the other of those two boxes, and Owen wins that game
  • Grace fills the last box
  • List the four games and check all three clues