Since you are given the two heights, you find the distance between the heights, which is the distance the hot air balloon traveled and divide it by the time it took.
Let's to that:
[tex]r = \frac{5515-3247}{56} [/tex]
Simplify:
[tex]r = \frac{2268}{56} [/tex]
[tex]r = 40.5[/tex]
So, your answer will be: The rate of descent of the hot air balloon is 40.5 feet/sec. It's constant, so we are thankful. If it weren't constant, we would have to use calculus.
