What quantity of pure acid must be added to 300mL od 50% acid solution to produce 60% acid solution?

Question

Mixture problem 

Answer 1

What quantity = x

Pure = 100%

50% = .5

 

So  1x + .5(300) = .6(x + 300)

 

This formula is in other words: 100% of x ml are added to 50% of 300ml to get 60% of the total (x+300)

 

Solving this gets you x = 75ml