An Asian restaurant sells fusion food with the choice of ketchup, mustard and relish. One day they serve 256 customers; 140 customers ordered Japanese food, 140 customers ordered Korean food, 84 customers ordered Japanese and Thai food, 62 customers ordered Korean but no Thai food, 68 customers ordered Japanese and Korean, 38 customers ordered all three kinds of food and 20 ordered none. a) The number of customers ordering Thai food is? b) The number of customers who did not order Thai food is?