Yeah, should be something along the lines of "... asks for a quarter of the remaining chocolate bars". Or maybe not. Who knows?

This sounds like some SAT "make questions harder by making them more confusing" bullshit.

It's a trick question. Tracey purposely asks for "the remaining quarter", which is inherently unclear. She then exploits Rachel's confusion to run off with all 16 chocolate bars.

People like Tracey should be behind bars (pun not intended).

While we are at it, the teacher needs a slap too.

That was obviously the correct answer.

OK, start with 16 and she takes 4, so you have 12 left.

Now of that 12 she wants a quarter of them, 1/4 x 12 = 3.

Add that 3 to the 4 she took at the start and you have 7 total.

The wording makes the question confusing.

Maybe it's like Tracey ends up with 4 chocolate bars and ¢25

The quarter wasn't about candy, Rachel slings all types of dope.

A quarter is 25% of anything. If she has 12 left, 25% is 3.

The 'remaining' quarter means a quarter of what is remaining of Rachel's pile. The phrasing is odd but there really isn't any way to misconstrue it without turning the meaning into nonsense that you can't do math on.