Final answer:
To evaluate (f ∙ g)(18), substitute 18 into both functions f(x) and g(x) and then multiply the results. In the context of the problem, (f ∙ g)(18) represents the cost per guest for an event where 18 guests have attended.
Step-by-step explanation:
To evaluate (f ∙ g)(18), we need to substitute 18 into both functions f(x) and g(x). First, substitute 18 into the function f(x) = 20 + 5x:
f(18) = 20 + 5(18) = 20 + 90 = 110
Next, substitute 18 into the function g(x) = 100 - x:
g(18) = 100 - 18 = 82
To evaluate (f ∙ g)(18), we multiply the values of f(18) and g(18):
(f ∙ g)(18) = 110 * 82 = 9020
In the context of the problem, (f ∙ g)(18) represents the cost per guest for an event where 18 guests have attended. The result, 9020, represents the total cost of catering for those 18 guests.