00:01
So we're starting out with 18 liters of 30 % acid, and we want to figure out how many liters of pure acid we need to add to get this concentration up to 50 % acid.
00:12
And so the first thing that i'm going to do is multiply the total amount of solution by our percent acid, but we're going to put our percent into a decimal point.
00:24
So 30 percent is 30 divided by 100 or 0 .3.
00:27
So we have 18 times 0 .3.
00:32
And this is going to give us the total amount of liters of acid in our solution.
00:37
So if we do this, 0 .3 times 18 is equal to, well, 18 times 2 is 36, and 36 plus 18 is 54.
00:48
So this is equal to 5 .4.
00:52
And this is the amount in liters of acid in our solution in this.
00:57
30 % acid solution.
00:59
So what we're going to do now is we're going to say 5 .4 plus x over 18 plus x is equal to 0 .5.
01:11
And the reason that we're doing this is in our original solution, our amount of acid and liters in our original solution was 5 .4...