Joshua Psalms T. answered 03/04/16
Tutor
5
(5)
Civil EIT, Former College Professor of Mathematics (in Asia)
f(x) = price, x = time
In minutes,
f(x) = x(1/15) ; 0 <= x <= 120
= 8 + (x-120)*(3/30) ; x >= 120
In hours,
f(x) = x(4/1) ; 0 <= x <= 2
= 8 + (x-2)*(6/1) ; x >= 2
Either is the answer depending on what unit do you wanna use. I put the fraction forms so that you can easily see that those are the rates.