00:01
So we're starting out with 20 gallons of 15 % alcohol.
00:04
And in order to figure out how many gallons of pure alcohol, we need to make this solution 25%.
00:11
The first thing we're going to do is we're going to multiply the amount of solution, which is 20 gallons times our percent alcohol.
00:20
And this will give us the amount of alcohol in our solution in gallons.
00:27
So if we do this, this is equal to three gallons.
00:32
So now we know that we have three gallons total of alcohol in our solution at this time, and we want to figure out how many more gallons we should add to get to 25 % alcohol.
00:43
So what i'm going to do is i'm going to set up a ratio where we have the amount of gallons of alcohol on the top or in the numerator, divided by the amount of gallons of our total solution.
00:57
So in this case it would be 20 plus x.
01:00
And we're going to make this equal to 0 .25, since we want the ratio of the amount of alcohol in our solution to the total amount of solution to be equal to 0 .25.
01:11
And this plus x is just going to be the added pure alcohol solution to our solution.
01:20
So that's why we're adding x...