Marginal costing - plz solve

It is Simple Equation
assume Variable cost per unit =X
assume Fixed cost per unit      =Y

Total Cost =   Variable Cost+Fixed Cost

& Toatal Cost= CPU * Units

Variable cost=V cpu* Units

Our Equation are:

1.  30000= 10000X+Y

2.  50000=20000X+Y

on solving this u will get X=Rs.2 which is Variable cost per unit.

now put x value in 1 Equation you will get Y=10000 which is Fixed Cost.