Quandaries
and Queries 

My question is how do you prepare a 100ml of a 30% alcohol solution using 95% alcohol? Justin (Student) Grade 10 

Hi Justin, You want to end up with 100ml of liquid, 30% of which is alcohol. 30% of 100ml is ^{30}/_{100}100 = 30 ml. Thus you need 30 ml of alcohol and 70 ml of water. The question now is, how much of the 95% solution do you need to give you 30 ml of alcohol? To ask this question using algebra, let x ml be the amount of the 95% solution that you need, then the question becomes
Said as an equation, solve for x if
Can you complete the problem now? Penny 

