Edited : I apologise I misunderstood the question.
You can solve the equation.
To find a percentage of a number, multiply by the decimal form of that percentage(20%=0.20). So, take the cost, $430, and multiply by common state sales tax (7% for me)---430 x 0.07 = 30.10 The sale tax rate is 7%.
All you need to do here is know where and how to plug in the numbers. In each equation, you'll have an initial fee, and an hourly fee, so your equation will be
y = i + hx, where i = the initial fee, and h = the hourly fee
So, after plugging them in, here's what you get:
Doors Galore: y = 40 + 50x
G&H: y = 60 + 40x
The average change of altitude per minute would simply be
the ratio of distance descended over time. That is:
average change of altitude = distance / time
average change of altitude = 0.44 mile / 0.8 minutes
<span>average change of altitude = 0.55 mile / minute</span>
