Comparing discounts
The narrator says Store C is better for fewer or odd numbers of cartridges, but for 1 cartridge Store B ($18) is cheapest and for 5 cartridges Store A ($80) beats Store C ($82.50). A try_it item tests 5 cartridges so students see the table method is safer than the rule.
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Alejandro compares ink cartridge prices at three stores with different deals: buy one get one half price, a flat $18 price, and 25% off orders of two or more. By working out the cost of three and four cartridges at each store, the video shows that Store C is cheapest for three and Store A is cheapest for four, and that things like return policy or distance may also matter.
You'll be able to
- work out the total cost of several items under different store deals.
- find a total after a percent discount by multiplying by what is left (25% off means x 0.75).
- compare deals and explain why the best store can change with how many items you buy.
Key words
- buy one, get one for half price
- For every item you buy at full price, the next one costs half price.
- flat rate
- The same price for every item, with no sale.
- percent off the total order
- A discount taken from the whole bill, such as 25% off everything when you buy two or more.
Transcript
- [Instructor] We're told, "Alejandro needs to buy ink cartridges for his printer. The table shows the prices and the advertised sales for the same type of ink cartridge at three different stores." All right, they show that over here. "Based on the advertised sales, at which store will Alejandro get the lowest price on three ink cartridges?
At which store will Alejandro get the lowest price on four ink cartridges? What are reasons why Alejandro might decide to buy his cartridges at each store?" So pause this video and try to work that out before we do that together. All right, now let's work this together.
And what I'm going to do is just set up some more columns to this table. So cost of three, I'll do in this column. And then I'll give myself some space right over here, and then I'll do cost of four. So at store A, it's buy one, get one for half price. So if Alejandro's buying three, that's only going to apply once, so he's going to have to buy one, another one for half price, so it's going to be 20 plus the one at half price, but then that third one is going to cost 20 again.
So this is going to be $50. Now the cost of four, he's going to be able to do that buy one, get one for half price twice. So it's going to be 20 plus 10, and then another full price, and then another half price one. And so he's going to be able to buy all of these for $60.
All of it for $60, I know my writing is a little bit small. All right, now let's get to store B. $18, no sale, just a flat rate. Alright, so three of them is just going to cost 3 times 18. 3 times 18, which is going to be $54. And four of them is just going to cost 4 times 18, which is going to be equal to, 4 times 18 is 60, let me make sure I'm doing this right.
3 times 18 is 30 plus 24. Yep, that's 54. 4 times 18 is 40 plus 32. That is $72. All right, and then last but not least, store C, buy two or more, get 25% off the total order. All right, so for three it's going to be 22 times 3, which is $66, times, so going to be 25% off the total order.
So that's the same thing as multiplying it times 75% or 0.75. Or another way to think about it, that's 3/4 of this right over here. And I could, let me just do that real fast with the calculator. So if I were to say 66 times 0.75, it equals 49.50, so it equals 49 50.
And then for the cost of four it would be $88. That's 4 times 22, it'd be $88 times 0.75. And so that is going to be 88 times 0.75 is equal to $66, is equal to $66. So let's see, for three, the best option is going to be store C. So we like this one. That's the cheapest, $49.50.
And for four, the best option looks like it is store A. Now, what are reasons why Alejandro might decide to buy his cartridges at each store? Well, if he's buying more cartridges, especially if it's an even number of more cartridges, store A is looking like a good option.
But if he is buying fewer cartridges or an odd number of cartridges, well then store C is looking like a better scenario. But in general, Alejandro should just do the table that that we just did. Now, there might be other considerations like their return policy or how close they are to his house or their customer service, et cetera.
But if we were just looking at price, we just did the analysis.
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