Question 999800

Plane  	speed	=x	mph							
wind   	speed	=y	mph							
against  	wind   	6	hours							
with	wind   	4	hours							
										
Distance against 		480	miles	distance with 		480	miles			
t=d/r	against	wind   		-						
480	/	(	x	-	y	)=	6			
6	(	x	-	y	)	=	480			
6	x	-	6	y	=	480	....................1			
										
480	/	(	x	+	y	)=	4.00			
4.00	(	x	+	y	)	=	480			
4.00	x	+	4.00	y	=	480	...............2			
Multiply (1) by	4    									
Multiply (2) by	6									24
we get										
24.00	x	+	-24	y	=	1920				
24.00	x	+	24	y	=	2880				
48	x	=	4800							
/	48									
x	=	100	mph							
										
plug value of x in (1)										
6	x		-6	y	=	480				
600			-6	y	=	480				
-6	y	=	480	-600						
-6	y	=	-120	mph						
	y	=	20							
Plane  	speed	100	mph							
wind   	speed	20	mph							
										
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