Ian is going to use a computer at an internet cafe. The cafe charges an initial fee to
use the computer and then an additional price per minute of usage. It is known that
the total charge to use a computer for 5 minutes would be $6 and that the additional
rate per minute of use is $0.40. Write an equation for the function C(t),
representing the total cost of using a computer for t minutes at the internet cafe.​