Critical Reasoning

Most parents who are generous are good parents, but some self-centered parents are also good parents. Yet all good parents share one characteristic: they are good listeners.
If all of the statements in the passage are true, which one of the following must also be true?
(A) All parents who are good listeners are good parents.
(B) Some parents who are good listeners are not good parent.
(C) Most parents who are good listeners are generous.
(D) Some parents who are good listeners are self-centered.
(E) Fewer self-centered parents than generous parents are good listeners.


What is the best approach to solve these typr of CR's

f2001290 wrote:some self-centered parents are also good parents. Yet all good parents share one characteristic: they are good listeners.

So,I guess its D?

I would go for D. Can someone please provide OA for this one?

Thanks.

I go for E

though ratio issue is involved in E, I consider D not obligatory

It cant be E, since we dont know the number of each type of parent.

Does anyone have OA for this one?

Thanks.

f2001290 wrote:Most parents who are generous are good parents, but some self-centered parents are also good parents. Yet all good parents share one characteristic: they are good listeners.
If all of the statements in the passage are true, which one of the following must also be true?
(A) All parents who are good listeners are good parents.
(B) Some parents who are good listeners are not good parent.
(C) Most parents who are good listeners are generous.
(D) Some parents who are good listeners are self-centered.
(E) Fewer self-centered parents than generous parents are good listeners.


What is the best approach to solve these typr of CR's

+1 for D

Whats the OA?

I can't say that I have seen an authentic conditional reasoning problem in the GMAT official problems but then again I haven't done all that many. Regardless I think this type is pretty rare.

INFORMAL WAY
(A) The premise states that all good parents are good listeners. It could be that all good listeners are good parents but not necessarily.

(B) This is similar to (A) but the opposite reasoning. It could be that some good listeners are not good parents but the premise allows for the possibility that all good listeners are good parents.

(C) Again, you can't even establish that most good listeners are good parents, nonetheless that most good parents are generous.

(D) From the premises you can say that some self centered parents are good listeners. This must mean that some good listeners are self centered. CORRECT

(E) You have no way to compare the quantity of these two.

FORMAL WAY
Premises
(1) Good Parents (ALL) Good Listeners
(2) Generous Parents (MOST) Good Parents
(3) Self Centered Parents (SOME) Good Parents

(A) When you flip the constituents in a premise with (ALL) the (ALL) changes to (SOME). Therefore (1) is akin to Good Listeners (SOME) Good Parents]. Statement (A) is too strong; we have only established that some good listeners are good parents.

(B) You cannot make this statement definitively because (SOME) could mean (ALL). There is no way to derive [Good Listeners (SOME) (not)Good Parents] from (1)

(C) Reversing (2) we have [Good Parents (SOME) Generous]. From the premises you can't even establish that most good parents are generous. In fact you can't even establish [Good Listener (SOME) Generous].

(D) Chaining (3) and (1) together we get [Self Centered Parents (SOME) Good Parents (ALL) Good Listeners] which leads to [Self Centered Parents (SOME) Good Listeners]. You can flip Constituents on either side of a (SOME) which gives you [Good Listeners (SOME) Self Centered Parents]. CORRECT

(E) Most means somewhere between 50-100%, some means 1-100%. Since you don't know actual numbers here you cannot compare these two quantities.

Go With (D)