Each of A, B, C, D, I, J and K has an exam on a different day of the same…
2026
Each of A, B, C, D, I, J and K has an exam on a different day of the same week, from Monday to Sunday. Exactly three people have exams between C and I. Exactly three people have exams between J and D. B has an exam before K and after A. Only D has an exam after I. How many people have exams after J?
Answer: D. Four — ConceptIn a seven-slot arrangement, if exactly three people lie between two people, their positions differ by four. An endpoint clue such as “only one person…
- A.
One
- B.
Three
- C.
Two
- D.
Four
Attempted by 21 students.
Show answer & explanation
Correct answer: D
Concept
In a seven-slot arrangement, if exactly three people lie between two people, their positions differ by four. An endpoint clue such as “only one person is after I” fixes I in the sixth slot and the sole later person in the seventh slot.
Application
Since only D has an exam after I, I must be on Saturday and D on Sunday.
C is four positions away from I, so C must be on Tuesday.
J is four positions away from D, so J must be on Wednesday.
The remaining days are Monday, Thursday and Friday for A, B and K. Because A is before B and B is before K, they occupy Monday, Thursday and Friday respectively.
The people after J are B, K, I and D, giving a count of four.
Complete arrangement
Day | Person |
|---|---|
Monday | A |
Tuesday | C |
Wednesday | J |
Thursday | B |
Friday | K |
Saturday | I |
Sunday | D |
Cross-check
The complete order from Monday to Sunday is A, C, J, B, K, I, D. Both four-position gaps and the A–B–K order are satisfied, and only D appears after I.
Contrast
One counts only D, which is the person after I rather than the full set after J.
Three omits one of B, K, I and D from the days after J.
Two counts only I and D, ignoring B and K, which also occur after J.
Four counts B, K, I and D, the four people placed after J.