Question

A, B and C are three students from Don School and P, Q and R are three students from Elite School. Q is brighter than R but duller than the Don School student who is brighter than A. The same Don School student is duller than P but is brighter than C.
Who is brightest amongst all?

• A. B
• B. P
• C. R
• D. Cannot be decided

Hint:

Work out which Don School student is meant, it has to be B, then chain all the brighter and duller relations together.

Answer 1

The Correct Option is B

A cleaner way to solve this is to build a brightness ladder step by step instead of chasing each clue one at a time.

1. Since A, B and C are the only three Don School students, the unnamed student described as brighter than A must be either B or C, because a person cannot be brighter than themselves, which rules out A.
2. The same student is later described as brighter than C, which rules out C as well, since C cannot be brighter than C. So this student has to be B.
3. Replace every mention of the Don School student with B: B is brighter than A, B is brighter than C, P is brighter than B, and B is brighter than Q.
4. Separately, Q is brighter than R, so combining with B brighter than Q gives the order B, then Q, then R.
5. Build the ladder from the top down. P sits above B. B sits above A, C and Q, with their exact order among themselves not fixed by the clues. Q sits above R at the very bottom.
6. Check the four options against this ladder. B is not at the top since P sits above it, so option B fails. R sits near the bottom, not the top, so option R fails. The ladder is fully connected from P down to R with no missing link at the top, so cannot be decided also fails.
7. Only P has nobody above it anywhere in the ladder, which confirms P is the brightest student among all six named students.