Berapa kemolaran larutan 20%berat c2h2oh(mr=40)?

wt = 20 gram
V = 80 gram = 80 mL
Mr = 40
M = ...................................?

M = wt/Mr x 1000/wp
    = 20/40 x 1000/80
    = 0,5 x 12,5
    = 6,25 molar