00:01
Alrighty, first thing i'm going to do is define our variables.
00:04
I'm going to say x equals liters of 15%, and i'm going to call y leaders of 33%.
00:20
Oops, 33%.
00:24
So we know that total we need 120 liters.
00:30
So x plus y has to equal 120.
00:34
And we know that ultimately our 120 liters is going to be 0 .21 or 21 % acid.
00:43
So the way we set this up is we can say x times 15%.
00:49
So i'm going to say 0 .15 times x plus 0 .3 times y is going to equal 120 times 0 .21.
01:02
So up here, we can say x equals y minus 120.
01:11
So if we plug that in, we can say 0 .15 times y minus 120 plus 0 .33y equals, and i'm going to do 120 times 0 .20 times 0 .21.
01:28
We get 25 .2.
01:31
So now we can say 0 .15 times y.
01:36
And then we know that 120 times 0 .15 is 18 and so we will add that to 0 .33y and we will get 25 .2 and so 0 .33 plus 0 .15 is 0 .48 so we get 0 .48 minus 18.
02:23
Nope, nope, nope.
02:26
Knew something didn't look right and it was not...