Problema Solution
How much pure acid should be mixed with 2 gallons of an 80% acid solution in order to get a 90% acid solution?
Answer provided by our tutors
You have 2 gal. @ 80%, which is .8*2 = 1.6 gal. of pure acid.
You need add 'x' gallons of 100% pure acid to make a 90% solution.
8*2 + 1*x = .9(2+x)
1.6 + x = 1.8 + .9x
multiply by 10 to eliminate decimals
16 + 10x = 18 + 9x
x = 2
Answer: Add 2 gallons of pure acid to 2 gallons of 80% acid to make a 90% acid solution.