the sum of squares of 3 numbers is 764 and sum of their products taken two at a time is 500 . what is their sum ?	Choose the correct answer:  A) 48  B) 42  C) 52  D) 32  E) 33

Rationale: description : let the numbers be x , y , z . = > x 2 + y 2 + z 2 = 764 = > 2 ( xy + yz + xz ) = 2 * 500 = 1000 = > ( x + y + z ) 2 = ( x 2 + y 2 + z 2 ) + 2 ( xy + yz + xz ) = 1764 = > ( x + y + z ) = sqrt ( 1764 ) = 42 answer b
Answer: B