Q18. Arrangements
MCQ · +3 / −1
What best can be concluded about the number of players coached by Zara?
- A) Exactly 2
- B) Either 2 or 3
- C) Exactly 3
- D) Either 2 or 3 or 4
Correct Answer
A) Exactly 2
Step-by-step solution
📌 Core Concept
The ratings are forced by the 1 to 7 scale and the average of 4. That fixes the coach of each player and gives Zara's count.
🔢 Step-by-Step Solution
1
Clue 3 says only Players 5 and 7 share a rating and everyone else is unique. So the eight ratings use all of 1 to 7, with one value repeated. Clue 4 gives a total of . Since , the repeated value is , so Players 5 and 7 each got 4.
2
Clue 1 of the coach rules: Yuki trains only even players and Zara only odd players. Players 1 and 4 share a coach (clue 2), and that coach must be Xena, because Player 1 is odd (not Yuki) and Player 4 is even (not Zara).
3
Players 2, 3 and 5 have three different coaches (clue 2). Player 3 and Player 5 are odd, so each is Xena's or Zara's, and they must differ. That leaves Player 2 with Yuki.
4
If Player 5 were Xena's, then Player 7 (same coach as Player 5) would be Xena's too, and Player 3 would be Zara's. Then Players 1, 5 and 7 are all Xena's, so Zara would have only Player 3. That breaks the rule that each coach trains at least two players.
5
So Player 3 is Xena's and Players 5 and 7 are Zara's. Zara's only possible odd players are 1, 3, 5, 7, and 1 and 3 are Xena's, so Zara trains exactly Players 5 and 7.
Quick Check
Zara's average is 4, Yuki's must be 6 and Xena's 3. This is consistent with the full solution (Xena: 1, 3, 4, 8; Yuki: 2, 6).
Correct Answer: A