Question 931150
plane  	speed	=x	mph					
wind   	speed	=y	mph					
against 	wind   	5	hours					
with 	wind   	3      	hours					
								
Distance with	wind   	900	miles		distance against	wind   	900	
t=d/r	against	wind   	(x-y)					
900.00	/	(	x	-	y	)=	5.00	
								
5.00	x	-	-5.00	y	=	900.00	....................1	
with	wind   	(x+y)						
900.00	/	(	x	+	y	)=	3.00	
3.00	(	x	+	y	)	=	900.00	
3.00	x	+	3.00	y	=	900.00	...............2	
Multiply (1) by	3.00							
Multiply (2) by	5.00							
we get	2.00							
15.00	x	+	-15.00	y	=	2700.00		
15.00	x	+	15.00	y	=	4500.00		
30.00	x	=	7200.00					
/	30.00							
x	=	240.00	mph					
								
plug value of x in (1)				y				
5.00	x		-5.00	y	=	900.00		
1200.00			-5.00	-1200.00	=	900.00		
-5.00	y	=	900.00					
-5.00	y	=	-300.00	mph				
	y	=	60.00					
plane  	240.00	mph						
wind   	60.00	mph