Question 486346
Copper	x	kg-------- $8.9						
Tin	y	kg--------$9.5						
								
1	x	+	1	y	=	15.3	.............1	
8.9	x	+	9.5	y	=	139.23	.............2	(9.1*15.3)
Eliminate y								
multiply (1)by 		-9.5						
Multiply (2) by		1						
-9.5	x		-9.5	y	=	-145.35		
8.9	x		9.5	y	=	139.23		
Add the two equations								
-0.6	x				=	-6.12		
/	-0.6							
x	=	10.20 kg			
plug value of 			x	in (1)				
1	x	+	1	y	=	15.3		
10.2		+	1	y	=	15.3		
			1	y	=	15.3		-10.2
			1	y	=	5.1		
				y	=	5.10kg