00:01
So we want to translate to a system of equations and solve this scenario.
00:04
Scientists need 65 liters of 15 % alcohol solution.
00:08
She has available 25 % and 12%.
00:11
How many liters of 25 %? how many liters of 12 % should she mix to make her, and we'll get rid of that, 15 % solution.
00:20
So i'm looking for the amount of 25 and amount of 10%, 12%.
00:24
So i'm going to call those just x and y.
00:27
If it's a total of 65 liters, i can model that with x plus y being 65.
00:33
With 25 % solution for x, i'm going to model that now with our percent solutions as 0 .25x plus 0 .1 to y.
00:43
And the goal is to get that to a 15%, so 0 .15, but if there's 65 liters, it's going to be 0 .15 times 65.
00:51
Okay.
00:52
So we're going to go ahead and just rewrite these again and multiply these two out.
00:54
So x plus y is equal to 65.
00:57
0 .25x plus 0 .25x plus 0 .12 .y.
01:01
Is equal to 0 .15 times 65, giving me 9 .75...