Sum of the squares of 3 no.'s is 138 and the sum of their products taken two at a time is 131. Find the sum? Select the correct option:
A) 20	B) 24	C) 26	D) 28	E) 30

Rationale: ( a + b + c ) 2 = a 2 + b 2 + c 2 + 2 ( ab + bc + ca ) = 138 + 2 * 131 a + b + c = √ 400 = 20 a
Answer: A