Question 722592
Helicopter 	speed	=x	mph					
wind   	speed	=y	mph					
against  	wind   	2.5	hours					
with	wind   	2	hours					
								
Distance against 		400	miles	distance with 		400	miles	
t=d/r	against	wind   		-				
400	/	(	x	-	y	)=	2.50	
3	(	x	-	y	)	=	400	
2.50	x	-	2.50	y	=	400.00	....................1	
								
400.00	/	(	x	+	y	)=	2.00	
2.00	(	x	+	y	)	=	400.00	
2.00	x	+	2.00	y	=	400.00	...............2	
Multiply (1) by	2.00							
Multiply (2) by	2.50							
we get				y				
5.00	x	+	-5.00	y	=	800.00		
5.00	x	+	5.00		=	1,000.00		
10.00	x	=	1,800.00					
/	10.00							
x	=	180.00	mph					
								
plug value of x in (1)				y				
2.50	x		-2.50	y	=	400.00		
450.00			-2.50	-450.00	=	400.00		
-2.50	y	=	400.00					
-2.50	y	=	-50.00	mph				
	y	=	20.00					
Helicopter 	speed	180.00	mph					
wind   	speed	20.00	mph					
								
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