Em, this is easier than it seems, I promise!
If we let w = the weight we are looking for, then we know that the first company charges 2w + 20 and the 2nd charges 3w + 10.
If the charges are the same, then the two are equal!
2w + 20 = 3w + 10
Subtracting 2w from both sides, we get 20 = w + 10. Subtracting 10 from both sides, we get 10 = w.
The weight that makes both companies charge the same is 10 pounds!
David W.
tutor
Em, x is always your input. I called it w in the problem. y is always your output. Let's take company 1. For 0 pounds, the first company is going to charge $20, so you'd start your graph at (0,20). For 1 pound, company 1 charges $22, so your next point would be (1,22). The charge for 2 pounds is $24 for a point at (2,24). It goes on from there.
Company 2 is going to charge $10 for 0 pounds, so your first point would be (0,10). One pound would put you at (1,13), and so on. Keep going until you end up with the same point on both lines, and that is your answer!
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05/28/15
Em P.
05/28/15