Question 33365
15 minutes is 900 secs.
Afer 900 secs the balloon will have risen by 8*900 = 7200 ft.
9.44 mph is 13.854 ft/sec
After 900 secs, the balloon has travelled horizontally by 900*13.854 = 12,468.8 ft.
That's 12,468.8 ft along and 7200 ft up.
By pythagoras' theorem the dist of the balloon from its launch point is {{{sqrt(12468.8^2 + 7200^2)}}} = 14,398.1
Dist = 14,400 ft
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