Answer:
65.5 feet per second
Explanation:
In order to calculate the rate of descent we first need to find the difference in heigh that the hot air balloon descended. We do this by subtracting the initial height from the end height like so...
6,039 - 3,288 = 2,751 ft
Now that we have the difference in height we need to divide this by 42 since that is the amount of time it took for this descent to occur.
2,751 ft / 42s = 65.5 ft/s
Finally we can see that the rate of descent was 65.5 feet per second