Question 998223
Plane  	speed	=x	mph					
wind   	speed	=y	mph					
against  	wind   	3	hours					
with	wind   	2.5	hours					
								
Distance against 		1800	miles	distance with 		1800	miles	
t=d/r	against	wind   		-				
1800	/	(	x	-	y	)=	3	
3	(	x	-	y	)	=	1800	
3	x	-	3	y	=	1800	....................1	
								
1800	/	(	x	+	y	)=	2.50	
2.50	(	x	+	y	)	=	1800	
2.50	x	+	2.50	y	=	1800	...............2	
Multiply (1) by	2 1/2							
Multiply (2) by	3							
we get								
7.50	x	+	-8	y	=	4500		
7.50	x	+	8	y	=	5400		
15	x	=	9900					
/	15							
x	=	660	mph 					
								
plug value of x in (1)								
3	x		-3	y	=	1800		
1980			-3	y	=	1800		
-3	y	=	1800	-1980				
-3	y	=	-180	mph				
	y	=	60					
Plane  	speed	660	mph 					
wind   	speed	60	mph 					
								
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