21 22 01:39:07 The cost, c, of a ham sandwich at a deli varies directly with the number of sandwiches, n. If c = $54

The price for 3 sandwiches amounts to $18. Since the cost, c, of a ham sandwich directly correlates with the quantity, n, and is told that c equals $54 for 9 sandwiches, the cost per sandwich is $6. Multiplying $6 by 3 gives a total of $18.