Question 485932
Plane	speed=	x	mph						
wind	speed=	y	mph						
with wind speed=		(x+y) 							
against wind speed		(x-y) 							
d=	540		with wind						
540	/	(x+y) 	=	2					
divide by 	2								
270	/	(x+y) 	=	1					
(x+y) 	=	270	............1						
d=	=	690	against 	wind					
27/(x-y) 	=	3							
divide by 	3								
690	/(x-y)	=	3						
	x	-		y	=	230	.............2		
add up (1) & (2)									
2	x	=	500						
/	2								
x=	250	mph	speed of	Plane	in still air				
plug value of x in (1)									
we get 	y= 	20	mph	speed of	wind