Let C=5x+40

Question

A.) Create a problem (real world situation) that would lead to this algebraic rule

B.) Identify the input and output variables

C.) Create a table of values corresponding to the following C-values: 50,60,70,and 80. This is not a typo; the values given were C-values and not x-values

D.) Are the above values reasonable in terms of the context you provided in part a? Explain why or why not.

E. Write a verbal rule for this equation

Answer 1

A. After a long train ride you arrive at what you think is your stop to realize you passed your stop 30 mins ago. Since this was the last train of the night you decide to take a cab home. You pay $40 to get admission and $5 for every mile you drive.

B. Your input variable is how many miles you drive (x) and your output variable is how much money you spend after riding in the cab (C)

C. Here is what your table (input) would look like based on the values of C (output):

1. C = $50 = $5x + $40; $5x = $10; x = 2 miles
2. C = $60 = $5x + $40; $5x = $20; x = 4 miles
3. C = $70 = $5x + $40; $5x = $30; x = 6 miles
4. C = $80 = $5x + $40; $5x = $40; x = 8 miles

D. Although the answers are correct, you most likely would not be charged $50 for travelling only 2 miles for a cab ride; so the values are not reasonable.

E. The cost of a cab fare (C) equals $40 for admission plus $5 per mile (x) driven.