Posted by Mikel on Tuesday, March 22, 2011 at 2:02pm.
An airplane can travel 380 miles into the wind in the same time that it can travel 420 miles with the wind. If the wind speed is 10 miles per hour, find the speed of the airplane without any wind.
Is this correct:
380(x10)=420(x+10)
380x3800=420x+4200
420x 420x
40x3800=4200
+3800 +3800
40x=8000
40x/40=8000/40
x=200
is 200 miles the answer?

Math  Mikel, Tuesday, March 22, 2011 at 2:20pm
*I have a correction:
380(x+10)=420(x10) 
Math  Damon, Tuesday, March 22, 2011 at 2:29pm
t (v10) = 380
t(v+10) = 420
380/(v10) = 420/(v+10)
so I get
380(v+10) = 420(v10) yes agree
40 v = 8000
v = 200 miles/hour 
Math  Mikel, Tuesday, March 22, 2011 at 2:34pm
Thanks