00:02
Jimmy has rented a telescope for $50 a week, and he uses it to let his friends have 30 -second looks at a baseball game nearby.
00:13
It cost him 20 cents to clean the eyepiece after each person has their turn, and we want to know what's our total revenue and marginal revenue.
00:23
Our first two columns have the demand curve for the peeps.
00:28
To get total revenue, we multiply along our demand curve.
00:32
Price times quantity.
00:35
So if our price is 90 cents and we have 150 peeps, total revenue would be 90 cents times 150 would be $135.
00:46
And we know that marginal revenue is a change in total revenue that you get when you sell one more unit.
00:54
So if we look at an output of 100 when we were charging a dollar, our total revenue there is 100.
01:02
If we lower the price to 90 cents we'll sell 50 more peeps and our total revenue will be 135.
01:11
So my change in total revenue would be $35, but that's not for one peep.
01:18
That's for selling 50 more so we have to divide by 50 and that gives us a marginal revenue of 70 cents.
01:26
All the other marginal revenues are calculated in exactly the same way.
01:32
Then we want to know if the marginal cost is 20 cents per peak, what's my profit maximizing output? so my rule is to maximize profit produce as long as marginal revenue is greater than or equal to marginal cost.
01:51
So if my marginal revenue is 20 cents, that's true all the way up to an output of 250 and a price to sell 250 according to our demand curve, we should charge 70 cents a peep...