SOLUTION: if a bird flies 40km/h with the wind,but only 10km/h against the wind , what is the rate of bird in still air? what is the rate of wind?

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Question 807785: if a bird flies 40km/h with the wind,but only 10km/h against the wind , what is the rate of bird in still air? what is the rate of wind?
Found 2 solutions by josmiceli, mananth:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +w+ = the rate of the wind
Let +b+ = the rate of the bird in still air
-----------------------
Going with the wind:
+b+%2B+w+=+40+ km/hr
Going against the wind:
+b+-+w+=+10+ km/hr
--------------------
Add the equations
+2b+-+50+
+b+=+25+
and
+b+%2B+w+=+40+
+25+%2B+w+=+40+
+w+=+15+
------------
The rate of the wind is 15 km/hr
The rate of the bird in still air is 25 km/hr

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Bird speed =x mph
wind speed =y mph

with wind speed = x+y = 40
against wind speed = x-y = 10
solve for x
2x=50
x= 25 km/h
plug x in x+y=40
y= 15 km/h