Question

The table below shows the outputs y for different inputs x:

Input
(x) 1 1 3 3
Output
(y) 4 2 12 6
Part A: Does the table represent y as a function of x? Justify your answer.
Part B: The total cost f(x), in dollars, for renting a paddleboat for x hours is shown below:
f(x) = 20 + 10x
What is the value of f(120), and what does f(120) represent?

Answer 1

Part A: The table does not represent y as a function of x. We can not input 1 and get 4 and 2 as outputs ( or input 3 and get 12 and 6 as outputs ).
Part B : f (120) is a cost for renting a peddleboat for 120 hours;
f (120) = 20 + 10 * 120 = 20 + 1,200 = 1,220.