At Deluxe paint store, Fuchsia paint is made by mixing 5 parts of red paint with 3 parts of blue paint. Mauve paint is made by mixing 4 parts of red paint with 5 parts blue paint. How many liters of blue paint must be added to 32 liters of Fuchsia to change it to Mauve paint? Pick:
A) 9	B) 13	C) 15	D) 16	E) 18

Rationale: "in 32 liters , red = 5 / 8 * 32 = 20 and blue = 12 so , 20 / ( 12 + x ) = 4 / 5 or , x = 13 ( answer b )"
Answer: B