Ellipses in Comparisons

I see.

Well, I'm not an expert, but will try to answer it based on my GMAT experiences.
Do we have ST1 and ST2 in the answer choices? If that is the case, so ST1 better than ST2, not necessarily that ST2 is wrong.

My point is, do we have another best option among the answer choices?
Sometimes I feel that the correct answer is not 100% satisfying answer, but it must be the best answer among all.

Just my 2 cents, good luck for our GMAT!

Hi DIII, are you sure ST1 is marked incorrect here? What is the explanation provided?

ST1 is correct, but ST2(ST1 without the "it did") is said wrong, due to wrong comparison.

Actually in ST2, since there is no verb explicitly mentioned after than, one would expect an explicit time indicator on the LHS of than (to match with the time indicator last year on the RHS of than).

So, following would be correct:

The practice took in 500$ more in revenue this year than last year.

The GMAT would claim that this is 'ambiguous'. (Which is fairly silly, in my opinion, since you and I both understand what the sentence is trying to communicate.) The problem is that you could read it as a comparison between a noun 'revenue' and a noun phrase 'last year', which is a nonsensical comparison. In other words, they say you could read it as being the same as this sentence:

I made 10$ more per hour from my day job than my evening job.
The practice took in 500$ more in revenue than last year.

Or, you could technically read it as a comparison between 'the practice' and 'last year':

John made 500$ more in tips than Miriam.
The practice took in 500$ more in revenue than last year.

In order to make it totally clear that you don't want the sentence to be read in those ways, you have to add in a few words ('it did'). That clarifies that you're comparing the amount that was made, not the year itself.

This is based on a problem from the Official Guide, by the way.

Thank you, makes sense.

Extending the topic, I wanted to post another query.

ST1: The books at this shop are much more interesting than any other shop.

ST2: This shop has more books than any other shop.

As per my understanding of omitting words, I think ST1 is wrong (because of the wrong comparison) and ST2 is correct.

What do you say?

You're correct. ST1 is wrong because it is comparing the books to "any other shop": The books...are...than any other shop.
ST2 is correct because it is comparing shop to shop: This shop...than any other shop