Final answer:
The slope-intercept equation for the cost line is y = x + 4, and another customer renting a bike for 4 hours would pay $8.
Step-by-step explanation:
The question involves finding the slope-intercept equation of a cost line for a bike rental company and calculating the cost for another customer based on the given information. Using Chet's rental, where he rented a bike for 6 hours and was charged $10, we can determine the initial fee and the hourly rate. The cost (y) for renting a bike can be represented by the equation y = mx + b, where m is the slope (hourly rate), and b is the y-intercept (initial fee).
Since Chet's cost was $10 for 6 hours, we can set up the equation 10 = 1(6) + b to find the initial fee. Solving for b gives us b = 10 - 6 = 4. Thus, the slope-intercept equation of the cost line is y = x + 4.
If another customer rents a bike for 4 hours, we can substitute x with 4 in the equation to calculate their cost: y = 1(4) + 4, which gives us y = $8. Therefore, the other customer should expect to pay $8 for renting the bike for 4 hours.
Based on the calculation above, we have identified the correct options as a) y = x + 4 and b) $8.