Answer: a)

b) Cost of a macadamia nut chip cookie is $33.93 and the cost of triple chocolate cookie. is $3.77
c) Elimination method because it enables us to eliminate one of the variables.
Explanation:
Let x be the cost of macadamia nut chip cookie and y be the cost of triple chocolate cookie.
Then according to the question we have the following equations:-

Multiplying 5 on both sides of the equation (2), we get
...............(3)
By using elimination method, subtract equation (1) from (3) we get

Substitute the value of y in (2), we get
