Answer: [tex]1800\text{ feet}[/tex]
Step-by-step explanation:
Given : Hot air balloons generally descend at a rate of 200 to 400 feet per minute.
Also, Four balloons descend 200 feet per minute for 9 minutes.
Then, the total change in altitude for all 4 balloons will be :-
[tex]200\times9=1800\text{ feet}[/tex]
Hence, the total change in altitude for all 4 balloons will be : Balloon descends 18 feet in 4 minutes.
