A sandwich store charges a $10 delivery fee and $4.50 for each sandwich.
a) If an office order 6 sandwiches, the total cost is:
10 + 6(4.50) = 10 + 27 = 37
Then, the cost of the order is $37
b) The total cost of x sandwich is given by the following algebraic equation:
f(x) = 10 + 4.50x
because 10 from the delivery fee and x sandwiches cost 4.50x dollars, f(x) is the total cost.
c) The relationship between the number of sandwiches and the cost of the order is proportional, because if the numbers of sandwiches increases, the cost increases too. It can be appreciated in the function f(x), which is a linear function with a unit rate of 4.50.
