Linear Models
It's a common practice to model real situations with linear equations.
The problem of cost, revenue, and profit for a business is a clear example of such a situation.
Let's analyze the store where Tom wants to sell hats. He calls x to the number of hats he expects to sell.
The costs involved in keeping his store up and running are (on a monthly basis):
* $3000 fixed. No matter if he sells or not
* $8 for each hat he offers
If he produces x hats, then the total costs are:
C(x) = 3000 + 8x
On the other hand, the income (revenue) of each hat sold is $20, thus for x hats, the revenue function is:
R(x) = 20x
The 'break-even' point is the value of x that makes the costs equal to the revenue. It's a no-loss no-profit situation.
Equating both functions:
3000 + 8x = 20x
We need to solve for x. Subtracting 8x:
3000 = 12x
Dividing by 12:
x = 3000 / 12
x = 250
Tom needs to sell 250 hats to break even.
If 251 or more hats are sold, Tom would start to have a positive profit