Whos on ill give you more points way more

What kinds of antigens are found on the rbcs of a person with a+ blood

The authors use the word “backbone” in lines 3 and 39 to indicate that

Case # 51173878 weighs 814 pounds; case # 51173981 weighs 803 pounds; case # 51174058 weighs 817 pounds; case 51174178 weighs 815 pounds; case # 51174248 weighs 817 pounds; case # 51174495 weighs 781 pounds; case # 51174577 weighs 828 pounds. what are the case #'s of the two cases that weigh the same amount?