Which of the following statements is necessarily true?
Answer and solution
Correct answer: B
Solution
Answer: B — V is a Marketing student.
1. There are exactly four Marketing students and four slots requiring one each, so each slot has exactly one Marketing student. J alone in Slot 3 is therefore Marketing. O is Strategy.
2. K, U are Operations. W guides K and L in the same department, so L is the third Operations student. The remaining J, M, N, V are Marketing.
3. W’s students K, L occupy Slots 1 and 2. U shares K’s slot and is consecutive to J in Slot 3, so K, U must be in Slot 2 and L in Slot 1.
4. Slot 2 also contains an A-guided Marketing student. A’s other student must be consecutive and cannot use Slot 3 (J is guided by Y), so is in Slot 1.
5. Y guides J in Slot 3 and the last Marketing student in Slot 4: Slot 2’s sole Marketing place is already assigned to A. Slots therefore have counts 2,3,1,2.
6. W guides L/K in Slots 1/2; A guides Marketing students in Slots 1/2; Y guides J and a Marketing student in Slots 3/4. X, Z guide U and O in either order. M, N, V can permute across Marketing places in Slots 1,2,4; 6×2=12 complete assignments remain.
Question-specific deduction:
K and U are Operations students, and L is also an Operations student because W guides both K and L and guides belong to the same department as their students. O is the only Strategy student. That accounts for all three Operations students and the one Strategy student.
The four remaining students — J, M, N and V — must therefore be the four Marketing students. Hence, V is definitely a Marketing student. X and Z can exchange the individual assignments to U and O, so neither of those guide assignments is individually certain. K is in Slot 2, not Slot 1. Option B is correct.
Verification: The four remaining students — J, M, N and V — must therefore be the four Marketing students. Hence, V is definitely a Marketing student. X and Z can exchange the individual assignments to U and O, so neither of those guide assignments is individually certain. K is in Slot 2, not Slot 1. Option B is correct.
1. There are exactly four Marketing students and four slots requiring one each, so each slot has exactly one Marketing student. J alone in Slot 3 is therefore Marketing. O is Strategy.
2. K, U are Operations. W guides K and L in the same department, so L is the third Operations student. The remaining J, M, N, V are Marketing.
3. W’s students K, L occupy Slots 1 and 2. U shares K’s slot and is consecutive to J in Slot 3, so K, U must be in Slot 2 and L in Slot 1.
4. Slot 2 also contains an A-guided Marketing student. A’s other student must be consecutive and cannot use Slot 3 (J is guided by Y), so is in Slot 1.
5. Y guides J in Slot 3 and the last Marketing student in Slot 4: Slot 2’s sole Marketing place is already assigned to A. Slots therefore have counts 2,3,1,2.
6. W guides L/K in Slots 1/2; A guides Marketing students in Slots 1/2; Y guides J and a Marketing student in Slots 3/4. X, Z guide U and O in either order. M, N, V can permute across Marketing places in Slots 1,2,4; 6×2=12 complete assignments remain.
Question-specific deduction:
K and U are Operations students, and L is also an Operations student because W guides both K and L and guides belong to the same department as their students. O is the only Strategy student. That accounts for all three Operations students and the one Strategy student.
The four remaining students — J, M, N and V — must therefore be the four Marketing students. Hence, V is definitely a Marketing student. X and Z can exchange the individual assignments to U and O, so neither of those guide assignments is individually certain. K is in Slot 2, not Slot 1. Option B is correct.
G Strategy shortcut
Method: Use four Marketing students across four slots: exactly one per slot. W puts K in Slot 2 and L in Slot 1; A then fills Marketing Slots 1/2, Y fills 3/4. Only the M/N/V permutation and X/Z swap remain.Verification: The four remaining students — J, M, N and V — must therefore be the four Marketing students. Hence, V is definitely a Marketing student. X and Z can exchange the individual assignments to U and O, so neither of those guide assignments is individually certain. K is in Slot 2, not Slot 1. Option B is correct.
G Strategy: Method: Use four Marketing students across four slots: exactly one per slot. W puts K in Slot 2 and L in Slot 1; A then fills Marketing Slots 1/2, Y fills 3/4. Only the M/N/V permutation and X/Z swap remain. Verification: The four remaining students — J, M, N and V — must therefore be the four Marketing students. Hence, V is definitely a Marketing student. X and Z can exchange the individual assignments to U and O, so neither of those guide assignments is individually certain. K is in Slot 2, not Slot 1. Option B is correct.