For the alcohol produced by the factory (the density is 0.8 × 10 to the third power of kg / M), the water content is required not to exceed 10%, so what is the range of alcohol density

For the alcohol produced by the factory (the density is 0.8 × 10 to the third power of kg / M), the water content is required not to exceed 10%, so what is the range of alcohol density

I calculated that your mistake may be that you didn't examine the topic clearly,
The requirement for a moisture content of not more than 10% is (by mass)
The answer 800 is no different, then look at the density of 10% water content
Because the water content is the mass ratio, the combination at this time is 9kg alcohol + 1kg water
Volume = 9 / 0.8 + 1 = 12.25m3
Density = 10kg / 12.25m3
About = 816 kg / m3