To have infinitely many solutions they must describe the same line. So any multiple or fraction of the reference line would indeed describe the same line, and thus "intersect" at each and every of an infinite number of points.
2(x+y=4)
2x+2y=8 (is the same line as x+y=4)
The median would be: 7.9
and the mean would be:7.4714285714 (you are able to chop that down a bit if needed)
Want it exact? Here it is:499.243083(got it from my calculator), if rounded, then here it is:500
4.5 to 6.5 i think not really shure
