Paul makes green paint. the ratio of yellow to blue is 2: 3. if he uses 1/5 ounce of yellow. how much blue should he use?

A. 3/10

Step-by-step explanation:

So the ratio is saying 2 units to 3 units.  What represents 1 unit when 1/5 is two units?  We cut it in half which is 1/10.

Now we have 1 unit so we can easily find three by multiplying by three, or even just adding three together.  So that's 3/10.  

let me knowif you don't quite get it.

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this