Question

The cost, c, of a ham sandwich at a deli varies directly with the number of sandwiches, n. If c = $54 when n is 9, what is the cost of the sandwiches when n is 3?

Answer 1

Using k as a constant of proportionality, we can write the mathematical relationship between c and n as:

c = kn

When c = 54, n = 9

54 = k x 9

divide both sides by 9

k = 6

So,

c = 6n

when n = 3

c = 6 x 3

   = 18

Therefore, the cost when n is 3 is $18

Answer 2

Thank you for asking this question here is your answer:

$18 is the answer, because if c = 54 when n is 9 that means  

54/9= 6  

So the sandwich is $6 so you would replace 9 with 3  

54/3= 18 s

Which means that the sandwich costs $18

If there is any confusion please leave a comment below.