Among 35-45 years olds in Gowburg, some prefer music that

Zarrolou has posted a perfect answer already. I just want to systemize the question in another way. Hope it helps.

GENERAL INFO:

First of all, this is “MUST BE TRUE” question. There are some important notes about it. If you follow this instruction properly, you just need under 2 minutes to solve this question.

First rule of thumb: “NO NEW information accepted”.
Second rule: A correct answer MUST pass the “Fact test”.

There are ONLY 2 types of correct answer:
(1) Paraphrase (re-write parts of the stimulus in other way but keep the same meaning)
(2) Combination (combine two or more parts of the stimulus to make an inference)

ANALYZE THE STIMULUS:

Fact #1: Among 35-45 years olds in Gowburg, some (G1) prefer music-20 years ago, others (G2) prefer music-pop today.
Fact #2: Children and spouses of G1 are themselves three times as likely as others [general population] in Gowburg to prefer music that was popular twenty years ago.
Fact #3: Children of G2 are ten times more likely than others [general populations] in Gowburg to prefer music that is popular today
Fact #4: Spouses of G2 are no more likely than other residents of Gowburg to prefer such music.


ANALYZE EACH ANSWER:

A) Parents who prefer music that is popular today are more likely to have musical tastes in common with their children than with their spouses.
Correct. This is the combination of fact #2 and fact #3. If you still doubt about it, just leave it as contender, move quickly to other options to eliminate the WRONG answers. Please keep in mind, in CR eliminate wrong answers always is easier than determine the correct one.

B) Unmarried adults are more likely to prefer music that was popular twenty years ago than music that is popular today.
Wrong. Nothing about “unmarried adults”. ==> Out immediately.

C) Parents who do not have musical preferences are less likely than the general population to have spouses who have musical preferences.
Wrong. Nothing about “people who do not have musical preferences”. Do not hesitate, eliminate it right away if you want to save time. Just stick to the facts: G1- people like old music + their children + spouses and G2-people like today pop music + their children + spouses.

D) Children of people who prefer music that was popular twenty years ago are not more likely than the general population to prefer music that was popular 20 years ago.
Wrong. D is a contradict option. D says: Children of G1 are not more likely than general population to prefer music 20 years ago. But fact #2 says: Children of G1 are 3 times more likely…….

E) Between 10% and 30 % of children prefer either musical that is popular today or music that was popular twenty years ago.
Wrong. Nothing about 10% and 30% because you DO NOT see any percentage info in the stimulus. ==> Out immediately.


TAKEAWAY:
In “Must be true” quesiton:
(1) NO new info accepted
(2) A correct answe MUST pass the fact test
(3) Eliminate a WRONG is easier than determine a CORRECT.

Hope it helps.