How many counters are there if three pupil had a bag each and one pupil had two more than one and?

A has 1 bag, B has 2 bags, C has 4 bags (or 8 if you mean pupil B not A, It is not clear from "as the other" if you mean the first or second pupil..)

a = a
b = a x 2
c = a x 4 (or b x 4)