A customer bought a product at the shop. However, the shopkeeper increased the price of the product by 15% so that the customer could not buy the required amount of the product. The customer managed to buy only 60% of the required amount. What is the difference in the amount of money that the customer paid for the second purchase compared to the first purchase?
Choose the most appropriate option:
A) 27 %	B) 29 %	C) 31 %	D) 33 %	E) 35 %

Rationale: "let x be the amount of money paid for the first purchase . the second time , the customer paid 0.6 ( 1.15 x ) = 0.69 x . the difference is 31 % . the answer is c ."
Answer: C