00:01
Okay, so we have a movie theatre with a fixed cost of $5 ,000 per day, and variable cost averaging $2 per customer, and the theatre charges $7 per customer.
00:13
We want to know how many customers per day does the theatre need in order to make a profit, and we want to find the cost and revenue functions and graph them on the same axes.
00:23
So i'm going to find the cost and revenue functions first, because this just makes part a easier.
00:28
So if we have that n is the number of customers, well, per day, the cost is going to be a function of n, and it's going to be 5 ,000.
00:45
So every day we have to pay 5 ,000 in costs, plus $2 per customer.
00:52
So 5 ,000 plus 2 times the number of customers.
00:55
This is going to be the cost function, c of n, and the revenue function, sorry, revenue as a function of n, or every customer that comes in pay $7, so it's just going to be seven times the number of customers n.
01:11
So this is the cost function, this is the revenue function, and we can use this for part a.
01:17
How many customers per day does the theatre need in order to make a profit? well, we can write the profit function if we want.
01:24
This is just going to be the revenue function, r of n, minus the costs.
01:30
So the revenue minus the costs, which is 5 ,000, no, not 5 ,000, sorry, this is mistake.
01:42
7n minus 5 ,000 minus 2n, which is 5n minus 5 ,000.
01:53
And we want there to be a profit.
01:56
So we want this function to be greater than 0.
01:58
So if this function is less than zero, this means we're making losses...