331/3% is about 110%
10% of 12 is 1.2
(12x0.1=1.2)
100% of 12 is 12
using the two values, 110% of 12 is 13.2.
since you are gaining 110%, you are getting 13.2 more ounces which gives you a final volume of 25.2 ounces.
(12ounces + 13.2ounces=25.2ounces)