Answer:
The equation for the price, as a function of time in hours is:
P(x) = 20*x for 0 ≤ x ≤ 2
P(x) = 40 + 10*(x - 2) for 2 ≤ x
Now, we want to evaluate this function in 40 mins.
we know that 1 hour = 60mins.
Then 40 mins = (40/60) hours = 0.67 hours.
Then we input this in our function, and because this is smaller than 2, we use the first piece of our function:
P(0.67) = 20*0.67 = 13.4
So in 40 mins, the charge will be 13.4 pesos.