A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rools were sold by noon and 80% of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

প্রশ্নঃ A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rools were sold by noon and 80% of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?