Simplify the question in the picture

Apackage of bacon holds 15 strips of bacon. the pancake house uses 17 packages of bacon in the morning and 21 packages in the afternoon. how many more strips were used in the afternoon than the morning?

Which one ? is the answer and how to find this answer

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin.how many doctors use brand x aspirin