Hot air balloons generally descend at a rate of 200 to 400 feet per minute. Four balloons descend 295 feet per minute for 7 minutes. Find the total change in altitude for all 4 balloons.

make a proportion

Let x = the amount of feet descended in 3 minutes (thus the total change of altitude of the balloon)

320 (feet per minute) / 1 (minute) = x (feet per minute) / 3 (minutes)

1) Divide: 320/1 = 320.

2) Multiply: 320 x 3 = 960.

The balloon that descends at a rate of 320 feet/minute (so, every minute, it descends 320 feet) descends a total of 960 feet in 3 minutes.

The balloon's total change in altitude is - 960 feet.