Question 912096
In the United States, proof is defined as double the percentage of alcohol contained in a solution at 60 degrees Fahrenheit or 15.6 degrees Celsius.
So it is the opposite of what you state.
200 proof is 100%
22 proof is 11%
38 proof is 19%
27 proof is 13.5%

We need a total of 13 oz. at 13.5% 27 proof
We want to know how many oz. at 11% 22 proof to mix with 19% 38 proof
a+b=13,
0.11*a+0.19*b=0.135*13
a=13-b
0.11*(13-b)+0.19*b=1.755
1.43-0.11b+0.19*b=1.755
0.08*b=0.325
b=4.0625
a=13-b
a=8.9375 oz. at 11% 22 proof
b=4.0625 oz. at 19% 38 proof
check
0.11*8.9375+0.19*4.0625=0.135*13
0.983125+0.771875=1.755
1.755=1.755
ok
codemx1