A hot air balloon begins at ground level . It then moves up at a rate of 5m/min. After 17 min, it moves down at a rate of 3 m/min for 6 min. Then , it moves up at a rate of 11/min. How high above the ground is the hot air balloon after 1 hour?
+129840 In the first 17 min...it rises 5 * 17 = 85 m
In the next 6 min it moves back down 3 * 6 = 18 m
There are [60 - 17 - 6] = 37 minutes left in the hour......so for this time...it rises back 11 * 37 = 407 m
So...after one hour...it is [85 - 18 + 407 ] m = 474 m above the ground
