If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

# Visualizing average costs and marginal costs as slope

Graphing variable cost, fixed cost and total cost. Created by Sal Khan.

## Want to join the conversation?

• When he explains the part where the programmers have less efficiency as he hires more and more programmers, is he describing the law of diminishing returns?
• Average Variable Cost and Average Total Cost curves have a negative slope at some points. Why are the values not negative in the table to reflect this negative slope?
• Excel displays negative numbers in parentheses (its an accounting cell format).
(50.00) = -50.00
(100.00) = -100.00
• This is certainly off topic, but I want to raise the question that was not addressed in these two videos. How many lines of code are required per month? In projects I've been involved with, the total lines of code required is estimated - usually with great precision by someone with experience. The amount of time available is determined, including time for testing and correcting at the module level and above. Only then would you determine staffing requirements, and if you had the situation Sal posited, but you needed 16,000 lines of code per month to meet the schedule, you would have to reorganize the project, or at least get a project manager with a better skill set for putting together the organization. Back to the question - what is the schedule requirement?
• Sal said we can also view the marginal cost on variable costs curve, but I calculate different value of slope on variable costs curve and total costs curve. Am I wrong?
• in this graph some of the independent values correspond to more than one "y"..
• No wonder this video is so long he needs to explain what a slope is to these not "idiots" but low IQ kids!
• How did Sal create this graph? I've created my own spreadsheet, similar to his but with different numbers, I just can't figure out how to graph it in excel.
(1 vote)
• how do I calculate the cost of debt
(1 vote)
• The cost of debt is normally considered to be the interest rate for that debt.
(1 vote)
• I'm guessing that around the world prices of gas, milk, certain types of meat, and eggs are all priced differently? If possible can I have a few of the variable prices?
(1 vote)
• Yes, prices of everything vary from place to place. The price of gas can vary from one side of the street to the other side (though usually only by a penny or two at most). Price also varies with time, so any particular price someone gives here would be out of date shortly after they submit it.
(1 vote)