Here's a question, like many on the GMAT, that can be solved with logic and estimation and NO ACTUAL MATH. The GMAT is a test of logic and ability to think under time pressure, not of basic arithmetic. If you did this mathematically, you may have arrived at the right answer but probably took too much time.
After reviewing the answer choices, group together A and C versus B, D and E. What is similar about these groups? A and C imply that the smaller bag costs less while the B, D, and E imply the smaller bag costs more. Which outcome makes more sense - A and C. Eliminate B, D, and E.
Now, does the new bag cost 1.5 cents? No way - not even close. Eliminate C.
A is correct.
This type of logic can help you on
OG2019 PS 8 (are the results of each little bracketed subtraction positive or negative)
OG2019 PS 47 (Positive or negative, large or small)
OG2019 PG 62
And many, many others