Question 593731

let him drive x miles on Highway
y miles in city
Total miles traveled

x+y = 397..........(1)

Consumption on Highway + consumption in city = Total consumption

x/36 + y/31= 12

31x+36y= 12*31*36
3136yy =13392.........(2)

x		miles on highway						
y		miles in city						
							
1	x	+	1	y	=	397	.............1	
								
31.00	x	+	36.00	y	=	13392	.............2	
Eliminate	y							
multiply (1)by		-36						
Multiply (2) by		1						
-36	x		-36	y	=	-14292		
31.00	x	+	36	y	=	13392		
Add the two equations								
-5.00	x				=	-900		
/	-5.00							
x	=	180.00						
plug value of			x	in (1)				
1.00	x	+	1.00	y	=	397.00		
180.00		+	1.00	y	=	397.00		
			1.00	y	=	397.00	+	-180.00
			1.00	y	=	217.00		
				y	=	217.00		
180		miles on highway						
217		miles in city						
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