Question 802658
Plane  	speed	=x	mph						
wind   	speed	=y	mph						
against  	wind   	3	hours						
with	wind   	2.5	hours						
									
Distance against 		420	miles	distance with 		420	miles		
t=d/r	against	wind   		-					
420.00	/	(	x	-	y	)=	3.00		
3.00	(	x	-	y	)	=	2.50		
3.00	x	-	3.00	y	=	420.00	....................1		
									
420.00	/	(	x	+	y	)=	2.50		
2.50	(	x	+	y	)	=	420.00		
2.50	x	+	2.50	y	=	420.00	...............2		
Multiply (1) by	2.50								
Multiply (2) by	3.00								
we get									
7.50	x	+	-7.50	y	=	1050.00			
7.50	x	+	7.50	y	=	1260.00			
15.00	x	=	2310.00						
/	15.00								
x	=	154.00	mph						
									
plug value of x in (1)				y					
3.00	x		-3.00	y	=	420.00			
462.00			-3.00	-462.00	=	420.00			
-3.00	y	=	420.00						
-3.00	y	=	-42.00	mph					
	y	=	14.00						
Plane  	speed	154.00	mph						
wind   	speed	14.00	mph						
									
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