hot air balloons generally descend at a rate of 200 to 400 feet per minute. a baloon descends 235 feet minute for 4 minutes. what is the balloons total movement?

Which means that if its descending at the consistent rate for 235 for four minutes then we set x= to number of minutes which is f(x)=235x = f(4)=235(4) = 940 feet downwards is the total movement of the hot air balloon