00:02
Okay, a biologist has two brine solutions, one containing 5 % salt and another containing 20 % salt.
00:09
How many milliliters of each solution should be mixed to have a 14 % solution in the end? so what we're going to do is we're going to take a 5 % solution and mix it with a 20 % solution.
00:28
So this 5 % solution is going to be x.
00:35
And then the 20 % solution is 1 minus x.
00:43
Okay.
00:45
And then eventually we're going to end with the 14 % solution.
00:51
So we got to find the algebraic expression that puts this all together, which i have started here a little bit, and you can see that they're all decimals.
01:04
So as i write out the whole expression, i'm going to multiply it by 100, oh goodness, to reduce the decimals.
01:21
So i'm going to start with 5x, and i'm going to add 20 minus 20x.
01:48
Oh, my mouse is kind of sticky today, sorry.
01:54
Minus 20x equals 14 for the 14 liters.
02:01
So putting to this together, 5x minus 20x is 15x, and then we can subtract the 20 from the other side.
02:16
So 20 minus 14 is a negative 6.
02:22
And i have a negative on both sides.
02:25
So i can take the negative off by making them both positive...