A Shopkeeper earns a profit of 12% on selling a book at 10% discount on the printed. The ratio of the cost price and the printed price of the book is:

A. 45:56
B. 50:61
C. 99:125
D. None of these
Explanation:
Printed price of the book is Rs. 100
After a discount of 10% S.P = Rs. 90
Profit earned = 12%
C.P of the book = Rs. (100/112 × 90) = Rs. 1125/14
(C.P) : (Printed price) = 1125/14 : 100 or 45 : 56