DS CAT question

[student]

If Sarah was 21 years old exactly 5 years ago, how old was Larry exactly 9 years ago?

(1) Larry is now twice Sarah's age.

(2) Twelve years ago, Jill was 6 years older than Sarah and 20 years younger than Larry.


Answer given is D. Shouldn't it be A?


This is the MGMAT explanation.

We know that Sarah was 21 years old 5 years ago. This means she is now 26 years old. The question asks for Larry's age 9 years ago. If we know Larry's age today, we can certainly figure out how old he was 9 years ago. Therefore, we can rephrase the question as: "How old is Larry today?"

(1) SUFFICIENT: Again, we know Sarah is 26 years old today. If Larry is twice Sarah's age, he must be 52 years old.

(2) SUFFICIENT: If Jill was 6 years older than Sarah and 20 years younger than Larry 12 years ago, Sarah and Larry must be separated by 6 + 20 = 26 years. If Sarah is now 26 years old, Larry must be 52 years old.

The correct answer is D.

How is the bolded statement above determined? Is this explanation suffering from information carryover or am I missing something?

[student]

That was my original post. I reworked it and now understand how to get the answer, but the explanation didn't help me solve it.

[RonPurewal]

How is the bolded statement above determined? Is this explanation suffering from information carryover or am I missing something?

no information carryover.

jill is a middleman (or, more appropriately, middlewoman) here, but she isn't terribly necessary to the calculation. think of it as a number line:
sarah ------6 YEARS------ jill ------20 YEARS------ larry
this means that larry and sarah are separated by 26 years.