User blog comment:Sparklyplatypus/"Are You Smarter Than an Xth Grader?"/@comment-1251488-20111115130816/@comment-3209350-20111115154409

Uhm... let's see

2x+y=10 x+y=7 - x   =3

2*3 + y = 10 6+y = 10 y = 4 :D