A is two years older than B who is twice as old as C. If the total of the ages of A, B and C be 12, the how old is B? Pick:
A) 10 years
B) 4 years
C) 6 years
D) 15 years
E) 16 years

Rationale: "let c ' s age be x years . then , b ' s age = 2 x years . a ' s age = ( 2 x + 2 ) years . ( 2 x + 2 ) + 2 x + x = 12 5 x = 10 x = 2 . hence , b ' s age = 2 x = 4 years . b )"
Answer: B