SOLUTION: The sanderling is a small shorebird about 6.5 in. long, with a thin, dark bill and a wide, white wing stripe. If a sanderling can fly 30 mi with the wind in the same time it can f

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Question 758580: The sanderling is a small shorebird about 6.5 in. long, with a thin, dark bill and a wide, white wing stripe. If a sanderling can fly 30 mi with the wind in the same time it can fly 18 mi against the wind when the wind speed is 8 mph, what is the speed of the bird in still air?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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If a sanderling can fly 30 mi with the wind in the same time it can
fly 18 mi against the wind when the wind speed is 8 mph,
what is the speed of the bird in still air?
:
Let s = bird speed in still air
then
(s+8) = ground speed of the bird with the wind
and
(s-8) = ground speed against the wind
:
Write a time equation; time = dist/speed
:
30%2F%28%28s%2B8%29%29 = 18%2F%28%28s-8%29%29
cross multiply
30(s-8) = 18(s+8)
30s - 240 = 18s + 144
30s - 18s = 144 + 240
12s = 384
s = 384/12
s = 32 mph is the speed in still air
:
:
Check this by finding the time of each way, should be equal
With: 30/40 = .75 hrs
Against: 18/24 = .75 hrs