Fifty two thousand fifty two is equal to 52,052.
D. 16 people. Just count all numbers until 88.
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)

It's still just easier to add first though.