00:01
So what i'm going to do here is i'm going to break down what my overall grade, course grade is.
00:04
I know that it's going to be 80 % and 80 % as a decimal 0 .8 of my test plus 20 % or as a decimal of my final.
00:18
And i know i want to get an a in the class.
00:22
So i want to get greater than or equal to.
00:24
I want this to be greater than or equal to 90 % or 0 .9.
00:29
Okay, rather i'm going to make this 90%.
00:36
So i want it greater than or equal to 90.
00:39
I know that my test scores, i'm given them my test scores for part a.
00:43
My average is 92%.
00:46
So i'm going to plug in 92 for 80.
00:49
And i'm trying to figure out what i need in my final.
00:51
So i'm going to call this just lowercase f, such that it's greater than or equal to 90.
00:57
Okay, so now let's go ahead and solve this.
00:59
I'm going to do 0 .8 times 92.
01:01
This will give me about 73 .6, copy down everything else.
01:07
And i'm just solving an inequality here.
01:10
Okay, so i'm trying to get f by itself.
01:12
I'm going to move 73 .6 to the other side.
01:17
So i'm going to subtract 73 .6 from both sides.
01:20
This will give me 0 .2f20f.
01:24
When i subtract from both sides, does that change the inequality.
01:27
It does not, the inequality only changes when i multiply.
01:31
Divide by a negative number.
01:33
And now get f by itself divided by 0 .20 or the same thing as 0 .2 to both sides.
01:41
So this will mean my final exam will need to be at least 82 % in order to get an a in this class...