Question 1013391
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S=speed in still air; W=wind speed
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S-W=410 mph
S=W+410 mph
,
S+W=490
(W+410mph)+W=490 mph
2W+410mph=490mph
2W=80mph
W=40mph
Wind speed is 40 mph.
.
S=W+410mph=40mph+410mph=450 mph
ANSWER: Speed in still air is 450 mph.