The average is (time)/(number of problems)=(45/60)/20=(3/4)/20=3/80 hours per problem. In minutes, the answer would be 3/80*60=9/4 minutes per problem.
B because there is only one negative and -63 divided by 7 equals -9. If it were -7 divided by 63 that would give you an answer in decimal form.
They are corresponding angles. Corresponding angles have equal measures.
