The product of two numbers is 120 and the sum of their squares is 289. The sum is:  Choose the correct answer:  A) 23  B) 21  C) 43  D) 56  E) 30

Rationale: "xy = 120 and x 2 + y 2 = 289 . ( x + y ) 2 = x 2 + y 2 + 2 xy = 289 + ( 2 x 120 ) = 529 x + y = 529 = 23 . answer a"
Answer: A