Question 1179659
Plane	speed	=x	mph	in still air					
wind	speed	=y	mph						
against wind  x-y		7.00	hours						
with wind  x+y		4.00	hours						
									
Distance = same=		1120	miles						
t=d/r									
1120	/	(	x	-	y	)=	7.00		
1120.00	/(	x	+		y)	=	4.00		
1	x		-1	y	=	160.00	....................1		
1120	/	(	x+	1	y	)=	4.00		
1120.00	/(	x	-	1	y)	=	4.00		
1.00	x	+	1.00	y	=	280.00	...............2		
Multiply (1) by	1.00								
Multiply (2) by	1.00								
we get									
1	x	+	1	y	=	160			
1	x	-	1	y	=	280			
2	x	=	440						
/	2								
x	=	220	mph						
									
plug value of x in (1)									
1	x		-1.00	y	=	160.00			
220			-1.00	y	=	160.00			
-	y	=	160	-220					
-	y	=	-60						
	y	=	60	mph