A photographer charges a sitting fee of $15, and charges $4 for each 5-in. by 7 in.photograph the customer orders. The linear function c = 15 + 4 n can be used to calculate the customer’s cost (c) based on the number of photographs (n) purchased. Determine the cost of 6 photographs.
a.
$24
b.
$39
c.
$114
d.
$25