#19 - Committee chairperson: No new course will be approved for next year’s schedule

[Administrator]

Complete Question Explanation

Must Be True. The correct answer choice is (C).

Answer choice (A):

Answer choice (B):

Answer choice (C): This is the correct answer choice.

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[dorsaltf]

Can someone please explain why the correct answer is C?

[Paul Popa]

Hey Salt, I'd be happy to! With MBT questions like this one, it's very important to study exactly what the stimulus is saying to make sure we're not picking an answer choice that is out of scope. The committee chairperson, in this case, says a lot of things, which we can boil down as follows:

1. If a new course is approved for next year, then a proposal for it has been received by the committee or by Dean Wilson. (This is an unless statement, but can be rewritten as a simple if...then statement as seen above.)
2. Dean Wilson only got one course proposal.
3. All of the proposals received by the committee have been for upper-level courses.
4. Beginning next year, all upper-level courses have prerequisites.

We can try and prephrase an answer here. Mine was: if a course received by the committee is approved, it will have at least one prerequisite. But truthfully, there's so many directions the correct answer can go in that we can't put too much stock in our prephrase (and sure enough, the correct answer doesn't match my prephrase. Yay! )

An important point to remember is that we don't know any specifics about Wilson's course proposal. It could be an upper-level course, but it might not be, and this point factors into some of the answer choices.

A) We can't say this for sure. While we're told that all upper-level courses will have prerequisites, we know nothing about lower-level or mid-level courses at this school. There's a possibility that the course received by Wilson is a special lower-level course that requires a prerequisite.

B) Careful: we're told that the committee received multiple courses, but there's no guarantee that they will approve all of them. For example, say they received five proposals for upper-level courses, and they approved three. Let's say Wilson rejected his, so those three are the only approvals for new courses. Yes, it's true that all of the new courses are upper-level, but its not true that the committee approved all of their proposals.

C) CORRECT. The key here is that Wilson received only one proposal. So if more than one is approved, and they can only come from either Wilson or the committee, that must mean that at least one came from the committee. Since they only received proposals for upper-level courses, and those must have prerequisites, it does follow that at least one of the approved courses in this instance carries a prerequisite.

D) The problem here is the second half: while it is possible that Wilson's submission is for an upper-level course, this answer makes a claim about ALL courses offered next year, whether new or not! This is a ridiculously broad statement; we can't make any determination about all courses offered at this school! This is a trap answer for students who are reading quickly and fail to notice that we're no longer talking about new courses specifically.

E) We can't know this. It could be the case that all new course proposals were rejected, including Wilson's and the committee's. Just because there are no new upper-level courses next year doesn't necessarily mean Wilson approved his: he could have also gotten an upper-level course and rejected it.

Hope this helps!

[kristinajohnson@berkeley.edu]

If the course is approved then the proposal was received by the committee or was received by the Dean. If the course is approved is the sufficient condition here, aren't we taking this condition for what it is, in this case the course is approved if the necessary conditions are met, and the necessary conditions are met: the committee received all upper level proposals, so some, or they received at least one, and the Dean received exactly one. The necessary conditions are met. I understand that the necessary conditions can be met or not met and then the sufficient condition can or can't occur, respectively. But if the sufficient condition is met than the necessary condition has to be met. In this case the only time the course could not be approved is if the proposal is not received by the committee AND the proposal is not received by the Dean. Via the contrapositive proposal NOT received by the committee AND proposal NOT received by the Dean then course is NOT approved. What am I missing here. Please help.

[Jeff Wren]

Hi kristina,

The first sentence in the stimulus contains a conditional statement using the word "unless." To correctly diagram this statement, use the Unless Equation.

Using the Unless Equation, the correct diagram would be:

NCA -> PRC or PRDW

which represents:

If a new course is approved, then either the proposal was received by the committee or the proposal was received by Dean Wilson)

This does not mean that if a proposal was received by the committee or the proposal was received by Dean Wilson, then the new course will be approved. That would be a Mistaken Reversal of the statement.

You wrote:

"If the course is approved is the sufficient condition here, aren't we taking this condition for what it is, in this case the course is approved if the necessary conditions are met"

This is not correct. You are confusing the relationship between the sufficient and necessary conditions. You are making an error that we refer to as a Mistaken Reversal, in which one incorrectly assumes that the necessary condition guarantees the sufficient condition.

The contrapositive of the original diagram would be:

Not PRC and Not PRDW -> Not NCA

which represents:

If the proposal was not received by the committee and the proposal was not received by Dean Wilson, then the new course is not approved.

Just to be clear, nothing in the original statement or its contrapositive indicates when a course will be approved, only when it will not be approved.

You wrote:

"In this case the only time the course could not be approved is if the proposal is not received by the committee AND the proposal is not received by the Dean."

Once again, this is incorrect for the same reason. A course can not be approved for any reason whatsoever; nothing in the stimulus limits when a course can be rejected. The only restriction provided is on what needs to be done to be approved.

Here's another example that may be helpful.

One cannot be accepted to Harvard Law School unless one applies to Harvard Law School.

Here, applying is the necessary condition to being accepted.

Of course, this does not mean that anyone who applies to Harvard Law School will be accepted.

In the same way, this does not mean that any proposal that was received by the committee or received by Dean Wilson will be approved.

More information on conditional reasoning, including the Unless Equation and Mistaken Reversals, can be found in "The Logical Reasoning Bible" or in any PowerScore LSAT course.