Question 913547
p=	speed of plane in still air							
w=	speed of plane in still air	wind						
 								
8	p		-8	w	=	1120	.............1	
								
7	p	+	7	w	=	1120	.............2	
Eliminate	y							
multiply (1)by		7						
Multiply (2) by		8						
56	p		-56	w	=	7840		
56	p	+	56	w	=	8960		
Add the two equations								
112	p				=	16800		
/	112							
p	=	150      						
plug value of			p	in (1)				
8	p		-8	w	=	1120		
1200			-8	w	=	1120		
			-8	w	=	1120		-1200
			-8	w	=	-80		
				w	=	10		
p=	150		speed of plane in still air					
w=	10		speed of wind				
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