The Barium Activity Number (BAN) was determined using the standard procedure. For this, 30 ml of 0.25N Ba(OH)₂ solution was used, in each of the three titrations, i.e. (a) blank titration, (b) back titration where mercerized fabric sample was immersed and (c) back titration where unmercerized fabric sample was immersed in Ba(OH)₂ solution. If the volume (ml) of 0.1N HCI consumed was 10, 1 and 4.5 respectively, the BAN of the mercerized sample, accurate to one decimal place, is