00:01
Bob went to a cafe and bought three coffees, a sandwich, and two jacket potatoes.
00:08
The price of the three coffees was one third the price of the sandwich.
00:17
So three coffees equals to one third price of the sandwich.
00:23
The two jacket potatoes in total cost $4 .75 more than the price of the sandwich.
00:31
So two potatoes plus $4 .75 equals the cost of the sandwich.
00:36
The total for everything was $16 .30.
00:43
So three cups of coffee, two potatoes, and a sandwich equals $16 .30.
00:50
How much did he pay for the coffees? so what we're going to do here is we need to solve this equation of the three coffees plus the two potatoes plus the sandwich equals $16 .30.
01:10
Well this is a lot of variables to try to find solutions to all at once.
01:15
So first thing we're going to do is find what each of our p and our c equal in terms of s.
01:26
So to start that off, we're going to start here with the three cups of coffee were in total were one third the price of the sandwich.
01:39
So three c equals one third s and we're trying to find what c is equal to.
01:47
So we're going to divide both sides by three.
01:54
So c is going to equal s over nine.
02:01
So the c here we're going to substitute s over nine.
02:05
And before i rewrite that, i'm going to go ahead and find what p is equal to.
02:09
So 2p plus 4 .75 equals s.
02:15
I'm going to subtract 4 .75 from both sides.
02:21
So 2p equals s minus 4 .75 and i'm going to divide each side by two.
02:34
So p equals s minus 4 .75 over two.
02:40
So this one is going to be s minus 4 .75 over two.
02:50
And now i can rewrite this equation with the variables that we have since found.
03:04
So three times s divided by nine, which is our coffee, plus two times s minus 4 .75 divided by two plus s.
03:29
And this is equal to 1630.
03:34
First thing that i'm going to do is go ahead and simplify out these different pieces.
03:42
So that way we are working with fewer pieces in the long run.
03:47
So we're going to start right here with the three times s over nine...