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Oops, sorry, forgot to add this.
Okay that makes more sense.
So... can you help me with setting up the problem?
Start with what you know. They sold 30 tickets of A, B, and C. So 30 = A + B + C. They sold twice as many tickets for B than A so 2A = B. And they made $5000 dollars; so 100A + 125B + 200c = 5000.
First thing to do is replace B with 2A in the equations. So 30 = A + 2A +C and 100A + 125(2A) + 200C = 5000. Then simplify. 30 = 3A + C and 100A + 250A + 200C = 5000, which simplifies further to 350A + 200C = 5000. And again to 7A + 4C = 100. Then you want to get one of your variables by itself. C is the easiest in the first equation; so 30 - 3A = C. Then replace C in the last equation; 7A + 4(30 - 3A) = 100. Simplify again to 7A + 120 - 12A = 100, then to 120 - 5A = 100, 120 = 100 + 5A, 20 = 5A, and finally 4 = A. Now you can plug that value back into your original equations and solve for B and C. 2(4) = B or B = 8. And 4 + 8 + C = 30 or C = 18.
Thank you! I struggled with this problem for an hour. Having equations to work with makes it easier.