How to make RUM 42.8% 75 proof by extra neutral alcohol?

Question

How to make RUM 42.8% 75 proof by extra neutral alcohol?

Answer 1

42.8% shows the strength in v/v (volume by volume) and 75 is the degree proof, now its degree can be adjusted by adding neutral alcohol.

Answer 2

Rum that is 42.8% alcohol would be 85.6 proof already. You would have to add water to make it 75 proof.  

Answer 3

Since 75 proof is 37.5pct alcohol, you need to add a negative amount of neutral alcohol.  I think you're a bit confused, try reading this:

http://en.wikipedia.org/wiki/Proof_(alco...