A milkman mixes 20 litres of water with 80 litres of milk. After selling one-fourth of this mixture, he adds water to replenish the quantity he has sold, what is the current proportion of water to milk?
a) 1 : 3
b) 2 : 3
c) 3 : 4
d) 4 : 3
e) None of these
a) 1 : 3
b) 2 : 3
c) 3 : 4
d) 4 : 3
e) None of these