Final answer:
The function for the total cost of using a computer for t minutes at the internet cafe, with an initial fee of $4 and an additional $0.40 per minute, is C(t) = 4 + 0.40t.
Step-by-step explanation:
We are given that the initial charge for using a computer at the internet cafe is $4, and for every minute of use, there is an additional charge. We also know that the total charge for 5 minutes of use is $6. To find the rate charged per minute, we can set up the following equation: $6 (total charge for 5 minutes) = $4 (initial fee) + $rate * 5 (minutes). By solving this equation, we find that the rate per minute is $0.40.
Now, we can write the equation for the function C(t), which represents the total cost of using a computer for t minutes at the internet cafe. The equation is C(t) = 4 + 0.40t. Here, $4 is the initial fee and 0.40 is the additional price per minute.