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 42 , the how old is b ?
"explanation : 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 = 42 ⇒ 5 x = 40 ⇒ x = 8 . hence , b ' s age = 2 x = 16 years . answer : a"
divide(multiply(subtract(42, const_2), const_2), add(const_4, const_1))