00:01
So we know that q stands for the number of hamburgs that will be sold, and that is controlled by the price in dollars.
00:17
And so we know that the revenue, in terms of the price, will equal the price times the number sold, and this is the number sold.
00:31
So we want to know in a, when will this model of p, and i'm already going to distribute it through, 1600p minus 200 p squared, when will that revenue equal $2 ,800? so we set it equal to zero, and we have 200 p squared minus 1 ,600 p plus 2 ,800.
01:03
And let's use, actually, let's divide everything by 200.
01:09
And when we divide everything by 200, we get p squared minus and 1 ,600 divided by 200.
01:17
Will end up giving us 8.
01:21
And then 2 ,800 divided by 200, we'll lose the 2 zeros, and then 2 goes into 2814 times.
01:29
And this, let's see, do i see if a factoring that's going to produce this? if i use the, i always like to try to factor if i can.
01:38
And if i use 2 and 7, that's not going to give me the right middle term.
01:43
And that's about 1 and 14.
01:44
It's definitely not going to work.
01:45
So let's go to quadratic formula.
01:47
So we have p is equal to 8 plus or minus the square root of 64 minus 4 times 1 times 14 all over 2a, which is 2.
02:00
And so we have that discriminant for 64 minus 4 times 14.
02:07
That discriminant is 8.
02:09
So this becomes 8 plus or minus the square root of 8.
02:14
And again, we're not, we want this in money.
02:17
I'm going to put this in my calculator and see what we get, 8 plus square root of 8.
02:25
And close my parentheses divided by 2.
02:28
The plus gives us, if we have a price of $5 .41, we'll get that...