00:01
All right, so in this problem, there's a school trying to figure out how to schedule or how many sections to offer.
00:06
So you can read the question.
00:09
It's there.
00:10
So here's what i did.
00:12
So i set up my variables, x equals the number of ancient history courses, sections.
00:22
Y is equal to the number of medieval sections.
00:28
And z is equal to the number of modern history sections.
00:34
And then i started making up some equations.
00:39
So i know there's only 46 total sections.
00:43
So x plus y plus z has to equal or be less than or equal to 46.
00:52
Okay.
00:54
Based on the number of professors, since ancient history only needs, needs one professor, i said x, and medieval only is one professor, so i said y.
01:05
But there's two professors needed for modern history, so two for every one of those modern sections.
01:15
And that's got to equal 62.
01:18
And now we base everything off the number of students.
01:22
So ancient history can hold 100, so that's 100x plus, and then the medieval can hold 50, so 50 y, and then the modern history can hold 200, 200 z and so that's the total of all the students, which is 5 ,300, or 5 ,300 students.
01:51
All right, so first equation is the sections.
01:56
This one came from the number of professors, that are available.
02:01
And this last one is students.
02:04
How many students? all right.
02:07
So we have three equations and three unknowns.
02:09
Now we just got to take them and try and chunk them down until we get the eliminate variables, find x, y, z.
02:17
That's what we need.
02:17
Okay.
02:19
So i'm going to start with these first two.
02:23
I'm going to take, for the professors, x plus y plus 2z, equal 60, and for the sections, x plus y plus z equals 46, and i'm going to subtract those because the x's will disappear, the y's will disappear, and 2z minus z is just z.
02:46
62 minus 46 is 16.
02:51
So that means z is going to be 16, so we should offer 16 sections of modern history.
03:01
Well, now that we know that z is 16, i could plug it in everywhere if i want...