Question 1171930
v of the 90%
20.9-v of the 46%


{{{90v+46(20.9-v)=70*20.9}}}---------do what you have to...




--
--

If you really wanted to think through using fraction meanings instead of as percents, and look at actual 'volume' of the alcohol then you could start as
{{{0.9v+0.46(20.9-v)=(0.7)(20.9)}}}
.
.
.