Math word problem

Question

Jack enrols in a fitness program. His totals cost is made up of a sign up fee and a cost per class, After 12 classes the total cost is $67 and after 14 classes the total cost is $74. What is the sign up fee?

Answer 1

It is a linear function: y = Mx + b

 

67 = M(12) + b = 12M + b

74 = M(14) + b = 14M + b

 

Subtracting the second equation from the first equation:

 

 14M - 12M = 74 - 67

2M = 7

M = 7/2 = 3.5

 

each class costs $3.50

 

67 = 12(3.50)+ b

67 = 42 + b

b = 67-42 = 25

 

The sign up fee is $25