Skip to main contentSkip to solution

The game of QUIET is played between two teams. Six teams, numbered 1, 2, 3, 4, 5, and 6, play in a QUIET tournament. These teams are divided equally into two groups. In the tournament, each team plays every other team in the same group only once, and each team in the other group exactly twice. The tournament has several rounds, each of which consists of a few games. Every team plays exactly one game in each round.

The following additional facts are known about the schedule of games in the tournament.

  1. Each team played against a team from the other group in Round 8.
  1. In Round 4 and Round 7, the match-ups, that is the pair of teams playing against each other, were identical. In Round 5 and Round 8, the match-ups were identical.
  1. Team 4 played Team 6 in both Round 1 and Round 2.
  1. Team 1 played Team 5 ONLY once and that was in Round 2.
  1. Team 3 played Team 4 in Round 3. Team 1 played Team 6 in Round 6.
  1. In Round 8, Team 3 played Team 6, while Team 2 played Team 5.

Which team among the teams numbered 2, 3, 4, and 5 was not part of the same group?

Solution

✅ Correct Option: 2
Slide 1/9
RoundGame 1Game 2Game 3
1
2
3
4
5
6
7
8

To solve this problem, you need to keep track of 3 important things:

  1. Team groups - Which teams belong to which group
  2. Match schedule - Which teams play each other in each round
  3. Games completed - Which games each team has already played

The problem states that each team plays 2 matches within the same group and 6 matches with teams from the other group.

Therefore, each team plays 2 + 6 = 8 matches total.

The total number of matches would be:

8 × 6 ÷ 2 = 24 (we divide by 2 to avoid counting duplicates, since T1 vs T3 is the same match as T3 vs T1)

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
4
53 vs 62 vs 5
61 vs 6
7
83 vs 62 vs 5

According to statements 3, 4, 5, and 6, this information can be directly filled in the table.

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
4
53 vs 62 vs 5
61 vs 6
7
83 vs 62 vs 5

According to statement 4:

Teams 1 and 5 played only once. Since the problem states that each team plays every other team in the same group only once, this means that teams 1 and 5 are in the same group.

Similarly, according to statement 3:

Teams 4 and 6 played in both round 1 and round 2. Since the problem states that each team plays each team in the other group exactly twice, this means teams 4 and 6 are in different groups.

Hence, we can conclude:

Group A: 1, 5, 6/4

Group B: 6/4

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
4
53 vs 62 vs 51 vs 4
61 vs 6
7
83 vs 62 vs 51 vs 4

According to statement 6:

In Round 8, each team played against a team from the other group (Point 1)

Since two of the matches are (Team 3 vs Team 6) and (Team 2 vs Team 5), the remaining match should be (Team 1 vs Team 4) (according to statement 1).

Using statement 2, which says that in Round 5 and Round 8, the match-ups were identical, we can determine the matches played in rounds 5 and 8.

From this analysis, we can determine that teams 3 & 6, 2 & 5, and 1 & 4 are in different groups.

Therefore, we can now complete the group assignments as:

Group A: 1, 5, 6

Group B: 4, 2, 3

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
44 vs 5
53 vs 62 vs 51 vs 4
61 vs 6
74 vs 5
83 vs 62 vs 51 vs 4

We know that Team 4 is in a different group from Teams 1, 5, and 6. Team 4 has already played two matches against Team 1 (in rounds 5 and 8) and two matches against Team 6 (in rounds 1 and 2).

Therefore, Team 4 must play two matches against Team 5.

These two matches can be scheduled in any two of the remaining rounds: 4, 6, or 7.

From statement 2, we know that the matches in rounds 4 and 7 are identical.

Therefore, the two matches between Team 4 and Team 5 are played in rounds 4 and 7. If it is played in round 6, then one would be in 4 or 7 which would make the total matches equal 3.

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
44 vs 5
53 vs 62 vs 51 vs 4
61 vs 64 vs 23 vs 5
74 vs 5
83 vs 62 vs 51 vs 4

Group A: 1, 5, 6

Group B: 4, 2,3

Team 4 has played in all rounds except Round 6.

The only remaining team it can play against in Round 6 is Team 2.

Moreover, the only remaining match in Round 6 can be between Team 3 and Team 5.

RoundGame 1Game 2Game 3
14 vs 6
24 vs 61 vs 5
33 vs 4
44 vs 52 vs 61 vs 3
53 vs 62 vs 51 vs 4
61 vs 64 vs 23 vs 5
74 vs 52 vs 61 vs 3
83 vs 62 vs 51 vs 4

Group A: 1, 5, 6

Group B: 4, 2, 3

Team 2 must play two matches against Team 6. These two matches can be scheduled in rounds 3, 4, or 7.

However, if the 2 vs 6 match is played in round 3, then the other match between them would need to be played in either round 4 or 7. This would contradict statement 2, which states that the matches in rounds 4 and 7 are identical.

Therefore, the two matches between Team 2 and Team 6 must be played in rounds 4 and 7. This automatically determines that the third match in both rounds 4 and 7 is between Team 1 and Team 3.

RoundGame 1Game 2Game 3
14 vs 61 vs 2
24 vs 61 vs 5
33 vs 41 vs 2
44 vs 52 vs 61 vs 3
53 vs 62 vs 51 vs 4
61 vs 64 vs 23 vs 5
74 vs 52 vs 61 vs 3
83 vs 62 vs 51 vs 4

Group A: 1, 5, 6

Group B: 4, 2, 3

Team 1 must play two matches against Team 2. These two matches fit perfectly in rounds 1 and 3.

RoundGame 1Game 2Game 3
14 vs 61 vs 23 vs 5
24 vs 61 vs 52 vs 3
33 vs 41 vs 25 vs 6
44 vs 52 vs 61 vs 3
53 vs 62 vs 51 vs 4
61 vs 64 vs 23 vs 5
74 vs 52 vs 61 vs 3
83 vs 62 vs 51 vs 4

We can fill the table with remaining matches to get the final table above.

Group A: 1, 5, 6

Group B: 4, 2, 3

2,3 and 4 are in the same group while team 5 is in different group

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question