john is 3 times as old as sam . if john will be twice as old as sam in 9 years , how old was sam two years ago ?
j = 3 s after 9 years j + 9 = 2 ( s + 9 ) j = 2 s + 9 2 s + 9 = 3 s s = 9 two years ago s = 9 - 2 = 7 e is the answer
subtract(subtract(multiply(const_2, 9), 9), const_2)