AboutAbe Mantell Expertise Hello, I am a college professor of mathematics and regularly teach all levels from elementary mathematics through differential equations, and would be happy to assist anyone with such questions!
Experience Over 15 years teaching at the college level.
Question I am helping a friend with her math for an upcoming test for adult education. It has been years since I have done this particular type of problem and cannot remember how to set it up. Thank you.
A 25 ounce solution is 20 percent alcohol. If 50 ounces of water are added to it. What percent of the new solution is alcohol?
Answer Hello Sarah,
20% of the 25 ounce solution is pure alcohol, thus only 5 ounces
are pure alcohol (i.e. 20% of 25 ounces). Now if we add 50 ounces
of pure water, we have a total of 75 ounces with 5 of the ounces
being pure alcohol. So the new concentration of alcohol is 5 parts
out of 75 or 5/75 = 0.066666... or 6 and 2/3 percent.
