my system 1 thinking: the sum of money is about 1, so each costs 1/2, but the bat costs 1 dollar too, so the bat is 1+1/2 = 3/2, and ball is 1/2. simples! wait… i forgot the .10. so bat costs 3/2.10 and 1/2.10 i guess
my system 2 thinking: i must do gaussian elimination!