Okay, guys, this is chapter 15 Problem. Nine were given this demand equation, total cost equation, marginal revenue and marginal cost equations. And we're told that international trade, at least to begin with, is prohibited. The first part of the question asks us What price? The monopoly company in Witten, um, charges for soccer balls. What quantity will they sell and how much profit the company makes? They are, as always, profit maximizing company's sets its price such that marginal cost equals marginal revenue. And so we have a marginal cost and marginal revenue equations here, so we're going to set them equal to each other. 10 minus two q equals one plus Q until nine equals three Q and three equals the quantity began. Plug this into the demand equation, which is 10 minus. Q equals P 10 minus three equals p, and so price is equal to seven. And we see that the revenue, which equals quantity times price equals three times seven equals 21. And so then we just need to determine pull up as we need to know what the cost is. And here we have, the total cost equals three plus Q plus 30.5 Q Squared, which equals three plus three plus 30.5 times three squared equal six plus half of nine, which is 4.5, equals 10.5. So profits equals 21 minus 10.5, which equals 10.5. The second part of the question asked us if we can, um, now opens up to trade at a world price of $6 and remember that our calculated domestic price is $7. What happens to domestic consumption? We'll have a domestic consumption or production. And what will Wickman become? An importer or exporter of soccer balls? Um, and so it says in the text book. Remember that if the domestic price is lower than the world price than the country become an exporter, and if the price the domestic price is higher than the world price actually, let's say is higher than the world price. Then the country will be an importer. And so, since the domestic price is $7 in the world, price was $6. What name is going to become an importer of soccer balls? So what happens to domestic production? Domestic production is going to decrease, and this is because the company is facing a lower price, and it's also facing an upward sloping, marginal cost curve. And if it can charge, if it can't charge as much, then it's going to have to produce less. Um, domestic consumption, however, is going to increase. And this is because the price of a soccer ball has decreased and they're facing a downward sloping demand curve, which means to lower the price. The more soccer balls they're going to demand in part d. This is asking us. Sorry, I skipped part C. Parsi is asking us if this analysis agrees with our analysis of international trade from chapter nine. I'm gonna let you review chapter nine. But the short answer is that yes, it does. Um, part D of this question is then asking us if the world price were exactly as we calculated in part a of the world price was $7 instead of $6. Would anything have changed in the weakening economy after it was opened up trade? And the answer is still yes, because the producer of soccer balls, uh, now has to be in a competitive market instead of a monopoly market. And this means that the company can no longer charge above. It's marginal revenue. And so when setting marginal cost equals marginal revenue to decide how much to produce, the company now has to set marginal cost equal to demand, to determine how much to produce. So this was Chapter 15 problem nine.