Answer: Hello there!
We know that a bag of apples weighs (7 + 7/8) lb and costs $10.88
But 1/18 of the apples are rotten, if we remove the rotten apples, we still have the other 17/18 portion of the bag to pay.
then; if the full bag costs $10.88, how much does it cost a 17/18 of the bag?
this is (17/18)*$10.88 = $10.28
Then if you remove 1/18 of the apples, the bag costs 10.28 dollars.
notice that I did not use the weight of the apples, in a lot of math problems you will have more information than the needed, and you need to know when the information is useful and when it is not.