Question 872604
If the populations are equal then y is same in both equations.

solve both equations 
6.950	x	+	1.000	y	=	903.740	.............1	
								
-2.450	x	+	1.000	y	=	743.940	.............2	
Eliminate	y							
multiply (1)by		-1.000						
Multiply (2) by		1.000						
-6.950	x		-1.000	y	=	-903.740		
-2.450	x	+	1.000	y	=	743.940		
Add the two equations								
-9.400	x				=	-159.800		
/	-9.400							
x	=	17 years	

1960 +17 = 1977 they were equal