GMAT Sentence Correction (SC) | Re: Officials at the United States Mint believe that the

Officials at the United States Mint believe that the Sacagawea dollar coin will be usedmore as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than four quarters, which weigh 5.67 gramseach.

A) more as a substitute for four quarters rather than for the dollar bill because its weight, only 8.1 grams, is far less than

--as mustdoit pointed out, the word "rather" does not belong here.

But even if you did not catch this, the phrase "its weight...is far less than four quarters" does not make sense.
It should be "its weight...is far less than that of four quarters."