Maybe Tacos took the diagram down?
I can see where he was going with this-- my first try took me 13:50 and I bet I could have shaved off some minutes by not drawing out all the contrapositives.
Well could anyone at least explain question (13)?
Thanks.
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- sheffieldjordan
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Re: Q13
This might be easier to understand with a diagram (we'll get one posted soon).
Meantime, here's the thinking: 4 Used are in, 1 is Out.
The question is, who's gonna be out? We should go to the constraints (or diagram) to see which pair of used cds is mutually exclusive and see where that goes. Looking at the last constraint, we can see that rap and soul are the mutually exclusive ones.
So if Used rap is in, used soul will be out, in which case new pop will be out, and at least one of the jazzes is In.
If Used soul is in, used rap will be out. This is answer choice (C).
Meantime, here's the thinking: 4 Used are in, 1 is Out.
The question is, who's gonna be out? We should go to the constraints (or diagram) to see which pair of used cds is mutually exclusive and see where that goes. Looking at the last constraint, we can see that rap and soul are the mutually exclusive ones.
So if Used rap is in, used soul will be out, in which case new pop will be out, and at least one of the jazzes is In.
If Used soul is in, used rap will be out. This is answer choice (C).
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Elle Woods
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Re: Q13
This is how I approached it:
4/5 Used CD's are the only one's in... so no new Cd is in.
This info alone eliminates (E); both Used Rap and Used Soul cannot be absent together.
Let's look at the remaining answer choices.
(A) If used Jazz is not on sale (remember: New Jazz is also not on sale), then NP and NS must be on sale. This is clearly wrong because the question states that no new CD's are on sale.
Therefore, Used Jazz has to be on sale; this also eliminates (D), which states that neither type of Jazz is one sale.
Now we are left with (B) and (C).
(B) If used opera is not in, that means that UJ, UP, UR and US are all in.
But we know from the last condition that "if either type of rap is on sale, then no soul is".
Thus, (B), which puts Used Rap and Used Soul together cannot be correct.
4/5 Used CD's are the only one's in... so no new Cd is in.
This info alone eliminates (E); both Used Rap and Used Soul cannot be absent together.
Let's look at the remaining answer choices.
(A) If used Jazz is not on sale (remember: New Jazz is also not on sale), then NP and NS must be on sale. This is clearly wrong because the question states that no new CD's are on sale.
Therefore, Used Jazz has to be on sale; this also eliminates (D), which states that neither type of Jazz is one sale.
Now we are left with (B) and (C).
(B) If used opera is not in, that means that UJ, UP, UR and US are all in.
But we know from the last condition that "if either type of rap is on sale, then no soul is".
Thus, (B), which puts Used Rap and Used Soul together cannot be correct.
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Re: Q13
The continued solutions from the diagram...
13. (C)
Question type: Conditional
Let’s use the new condition (four of the five used CD’s are the only CD’s on sale) to examine each answer choice. Since four of the answers must be false, it will most likely be easiest to try to eliminate the must be false answers.
(A) If UJ is not on sale, this means the other four used CD’s are on sale, including US and UR. Well, we can see from the first entry in the left column that if US is on sale, then UR is not. US and UR cannot both be on sale. Eliminate (A).
(B) Again, if UO is not on sale, this means the other four used CD’s are on sale, including US and UR. But US and UR cannot both be on sale. Eliminate (B).
(C) If UR is not on sale, then US, UP, UJ, and UO are on sale. This doesn’t seem to violate any rules, so let’s leave it for now and try to eliminate the other two.
(D) If neither type of jazz is on sale, then UJ is not on sale, which means the rest of the used CD’s are. Again, this means US and UR are both on sale. Impossible. Eliminate (D).
(E) This would put both UR and US off the list. But there are only five used CD’s! If four of them must be on sale, we can’t have both UR and US off the list. Eliminate (E)
We’re left with answer (C).
13. (C)
Question type: Conditional
Let’s use the new condition (four of the five used CD’s are the only CD’s on sale) to examine each answer choice. Since four of the answers must be false, it will most likely be easiest to try to eliminate the must be false answers.
(A) If UJ is not on sale, this means the other four used CD’s are on sale, including US and UR. Well, we can see from the first entry in the left column that if US is on sale, then UR is not. US and UR cannot both be on sale. Eliminate (A).
(B) Again, if UO is not on sale, this means the other four used CD’s are on sale, including US and UR. But US and UR cannot both be on sale. Eliminate (B).
(C) If UR is not on sale, then US, UP, UJ, and UO are on sale. This doesn’t seem to violate any rules, so let’s leave it for now and try to eliminate the other two.
(D) If neither type of jazz is on sale, then UJ is not on sale, which means the rest of the used CD’s are. Again, this means US and UR are both on sale. Impossible. Eliminate (D).
(E) This would put both UR and US off the list. But there are only five used CD’s! If four of them must be on sale, we can’t have both UR and US off the list. Eliminate (E)
We’re left with answer (C).
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