The sum of two numbers is 40 and their difference is 4. The ratio of the numbers is
Choose the most appropriate option
A) 11 : 9	B) 11 : 18	C) 21 : 19	D) 21 : 19	E) none

Rationale: sol . let the numbers be x and y . then , x + y / x - y = 40 / 4 = 10 ⇔ ( x + y ) = 10 ( x - y ) ⇔ 9 x = 11 y ⇔ x / y = 11 / 9 . answer a
Answer: A