Ruri Membeli Radio Bekas Dengan Harga

Video Transcript

All correct. And then this problem someone buys some radios for $1200. Nosotros don’t know how many there are then this dealer sells half of them and gives half of them away. When she sells the half that she does end upward selling, she charges $10 more per radio. And the outcome is Annette balance or breaking? Breaking even. So, I’ve set up the same blazon of model that we’ve been using all throughout this particular department. The rates at which she bought them, we don’t know, but the rate at which she sold them was $x more. Her radio, the number of, um, radios that she butts, nosotros don’t know the number of radios that she sold was half of the number that she bought, and the total for each is 1200. Now, there might exist, ah, better way to get about this. Merely this is the way that it made sense to me based off of the prepare. So now I’m going to write. These two equations are multiplied by end is equal to 1000 200 and our plus 10 multiplied by half of N is equal to 1200. I’g side by side. I’thousand going to solve for one of the variables in this offset equation, which is by far the to the lowest degree complicated of the two. Um and I’m gonna testify what happens in either of the situation. So the first is that we want to solve for end. If I want to solve for end, then I’m going to become end by itself by dividing by r S. O N is equal to 1200 divided by our ah ah unlike way that I could arroyo this is instead solving this equation for are so our is equal to 1200 divided by x. The number one’south a substitute whichever situation into though the other equation the i for selling. So in this case, if due north is 1200 over our then that’due south what goes in the place of cease here. And then this is our plus 10 times the quantity won thousands 200 over our huff, which is equal to 1200. All right, Um, that is incredibly complicated looking. So I’yard going to showtime by multiplying both sides by two. Information technology’s normal to buy this side by two problems will cancel out. Multiply this side by two. I become 2400 is equal to now. When I distribute this, I will get 1200. Are over are bold that our is not zilch, which information technology tin’t be because she’s making money. That ways that the ours will cancel so I’ll be left with 1200 in the second term. I have one thousands, 200 multiplied past 10 is 1200 over four. I’m going to combine light terms by subtracting 1200 from both sides. And so yard Sorry, 12,000 over our is equal to 1200. Then I will use cantankerous products. This is over one. So our times 1200 there’s 1200 are is equal to one times 12,000 and then I will divide both sides by 12,000. The number of 12 thousands that go Sorry, 1200 that go into 12,000 is 10. And then our equals x. Our goal is to find the number of radios that this person originally bought. So if our is ten and I put 10 in the place of the rates ten times 120 is equal to 1200 so north equals 120. So that’southward one style that we could solve it the other way that we could accept solved. This problem is if we had substituted for our outset. So if we substitute for our get-go, then that goes into this equation. Then instead of our it’due south 1200 over stop plus 10 quantity times cease plus Sorry. End over also. I’m going to distribute the cease plus sorry and over to to the 1200 over end. And the 10 when I distribute the ends will cancel in the first term. And so I’ll exist left with 1200 over besides, which is the aforementioned affair at 600 then in the second term will have 10 stop over too, which is same thing as five end equal to 1200. Next else attracts 600 from both sides. Five times the number is equal to 600. So we’ll split up both sides by 5. All right, and then then the value so equals 120 which confirms what we got here is well, so either one is complicated. It’s upwards to you whether y’all desire to solve for one of the variables and so come up dorsum and self for the one that y’all’re looking for, or if you desire to create an expression that allows you to solve more directly. But either way, the number that she needed to purchase was 120 buying them at $10 apiece. Then when she sells half of them for $xx apiece, she gets her money back, and she has friends who