# The exponential function f(x)=42.2(1.56)^x models the average amount spent, f(x), in dollars, at a shopping mall after x hours. What is the average amount spent, to the nearest dollar, after four hours?

Question
Exponential models
The exponential function $$f(x)=42.2(1.56)^x$$ models the average amount spent, f(x), in dollars, at a shopping mall after x hours. What is the average amount spent, to the nearest dollar, after four hours?

2021-03-12
Consider the given exponential function:
$$f(x)=42.2(1.56)^x$$
Where, f (x) is the average amount spent in dollars.
To Find:
The average amont spent after four hours:
Substitute $$x=4$$:
$$f(4)=42.2(1.56)^4$$
$$f(4)=42.2(5.92240896)$$
$$f(4)=249.9256$$
$$f(4)\approx250$$
Hence, the average amount spent after four years is $250. ### Relevant Questions asked 2021-05-26 You open a bank account to save for college and deposit$400 in the account. Each year, the balance in your account will increase $$5\%$$. a. Write a function that models your annual balance. b. What will be the total amount in your account after 7 yr? Use the exponential function and extend the table to answer part b.
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