Q5 - Most parents who are generous

[sonssi13]

Could someone explain the difference between C and D ?

Thanks

[ohthatpatrick]

(D) is provable from the facts we're provided, while (C) goes beyond what we know.

Some good parents are self-centered. All good parents are good listeners. So there must be at least one good parents who is self-centered and a good listener.

(C) is actually a mean backwards trap.

We know that most generous parents are good parents. We also know that all good parents are good listeners. We can combine those ideas to infer that MOST generous parents are good listeners.

But (C) goes backwards on that idea. MOST statements aren't reversible.

'Most Senators are men' does not mean that 'Most men are Senators'.

So when you're dealing with MOST, you need to be very careful about the order of ideas.

==== Here's a more formal discussion of what this problem is testing / how to approach it ====

First of all, just as a quick-n-dirty tip for problems such as these, you would immediately think that (B) and (D) are MUCH more likely to be the correct answer because they are more conservatively worded.

SOME is much safer than ALL, MOST, or FEWER.

To justify SOME, you only need one example.

Secondly, Inference questions that give you a handful of facts that involve quantity words (such as SOME/MOST/ALL, etc.) are basically testing you on two possible inferences.

1st, more typical one:
All A are B
+
Some A are C
=========
Some B are C (or Some C are B ... those mean the same thing)

2nd, more rare one:
Most A are B
+
Most A are C
===========
Some B are C (or Some C are B ... those mean the same thing)

Notice that in both cases, the inference we're allowed to draw is only that there is SOME overlap between B and C.

Notice also that in both cases we need 2 facts about the same group in order to draw an inference.

Looking quickly at the 3 statements they're giving us here, we're getting a MOST, a SOME, and an ALL.

We need 2 MOST statements to make that 2nd type of Inference. Since we only have 1 MOST statement, we're not going to be making that 2nd type of inference.

We'll be making the 1st type, pairing up the ALL statement with one of the other two facts we're told.

ALL 'good parents' are 'good listeners'
SOME 'good parents' are 'self-centered'
SOME 'good parents' are 'generous'

The possible inferences we could make are:
SOME good listeners are self-centered
or
SOME good listeners are generous

Hope this helps.

[hhylee88]

Is B not the right answer because it is a "could be true" and not "must be true"?