Total sale by shop A = 3500 (hardbound) + 2000 (paperback) = 5500
Total sale by shop C = 4400 (hardbound) + 5500 (paperback) = 9900
Total sale by A and C = 5500 + 9900 = 15,400
Total sale by shop B = 3900 (hardbound) + 5200 (paperback) = 9100
Total sale by shop D = 5500 (hardbound) + 6600 (paperback) = 12,100
Total sale by B and D = 9100 + 12,100 = 21,200
Required ratio = 15,400 : 21,200
= 77 : 106 (Divide both terms by 200)
Answer: 1. 77:106