Diagram

[nazu.s.shaikh]

Here is the question:

Doctor Yamata works only on Mondays, Tuesdays, Wednesdays, Fridays and Saturdays. She performs four different activities- lecturing, operating, treating patients, and conduction research. Each working day she performs exactly one activity in the morning and exactly one activity in the afternoon. During each week her work schedule must satisfy the following restrictions:

She performs operations on exactly three mornings.

If she operates on Monday, she does not operate on Tuesday.

She lectures in the afternoon on exactly two consecutive calendar days.

She treats patients on exactly one morning and exactly three afternoons.

She conducts research on exactly one morning.

On Saturday she neither lectures nor performs operations.

___________________________________________

This is how I drew it out.

A: __ __ __ _x_ __ __ TTT LL

M: __ __ __ _x_ __ __ OOO T R

M T W T F S

On the answer page of my work book they wrote this :
The first inference involves Saturday afternoon. According to the rules, Doctor Yamata can only lecture or treat patients in the afternoon. But on Saturday she cannot lecture, so it follows that she must treat patients and a "T" can be placed n Saturday afternoon.

My question here is : Why put a T in the afternoon, why cant we in the morning? Am I missing or overlooking a rule here?

[ManhattanPrepLSAT1]

We must put T on Saturday afternoon. Think about it... what can go on Saturday afternoon - only L or T. And they just said that L cannot go on Saturday afternoon.

Keep in mind that T could go on both Saturday morning and Saturday afternoon. Regardless, T must go on Saturday afternoon though.

I've posted a setup for this as well with all the deductions.

[yawhtsup]

hey. am new to this. i do not understand how we deducted that "L" is on tuesday afternoon?? why cantd it be on Wednesday?

[ManhattanPrepLSAT1]

There most definitely could be an L on Wednesday afternoon. But even though we don't know what is scheduled on Wednesday afternoon for sure, we can still infer that L must be scheduled on Tuesday afternoon. The reason for this is that there must be two consecutive L's in the afternoon. Those L's must be scheduled Mon/Tue or else Tue/Wed. Either way though, there must be an L on Tuesday afternoon.

Here's another way of looking at in case you're turned around on this example and need to see this in another context.

Given three numbers: 7, 8, and 9

Suppose you must take two consecutive numbers. Then you must select 7 and 8 or else 8 and 9. No matter what though, you're selecting an 8.

In this case "8" represents Tuesday afternoon. Does that help?

[yawhtsup]

yes. thank you very much!!