Question

A neurosurgeon, an orthopaedist, a plastic surgeon and an ophthalmologist visited the patient after a surgery. Times are: Neurosurgeon 7{:45, Orthopaedist 8{:}30, Plastic surgeon 9{:}15, Ophthalmologist 9{:}50 (each may be A.M. or P.M.). Who were the doctors to visit the patient in the evening?}

• A. Neurosurgeon and Plastic surgeon
• B. Plastic surgeon, Ophthalmologist and Neurosurgeon
• C. Orthopaedist and Neurosurgeon
• D. Ophthalmologist and Orthopaedist and Plastic surgeon

Hint:

When times can be A.M. or P.M., use the logical order constraints to place some visits in the morning and force the rest to the evening; then read off the required group.

Answer 1

The Correct Option is A

Step 1: Recall the day-order constraints from the setup.
- Ophthalmologist goes for rounds before the surgeons, but not first overall (i.e., some other doctor must go before him).
- Neurosurgeon is not last.

Step 2: Assign A.M./P.M. to satisfy the constraints.
Make the non-surgeons Orthopaedist and Ophthalmologist visit in the A.M. so Ophthalmologist is earlier than the surgeons yet not first:
Orthopaedist \(8{:}30\,\text{A.M.}\) (first), Ophthalmologist \(9{:}50\,\text{A.M.}\) (second).
Then place the surgeons in the P.M.: Neurosurgeon \(7{:}45\,\text{P.M.}\) (third), Plastic surgeon \(9{:}15\,\text{P.M.}\) (fourth).
This satisfies “Ophthalmologist before the surgeons,” “not first,” and “Neurosurgeon not last.”

Step 3: Identify evening visitors.
Evening (P.M.) visits are by the Neurosurgeon and the Plastic surgeon.

\[ \boxed{\text{Neurosurgeon\ and\ Plastic\ surgeon\ visited\ in\ the\ evening.}} \]