SOLUTION: Solve Problems Using Linear Systems 11. To join Karate Klub, David must pay a monthly fee of $25 and an initial fee of $200. If he chooses Kool Karate, he must pay an initial fee

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: Solve Problems Using Linear Systems 11. To join Karate Klub, David must pay a monthly fee of $25 and an initial fee of $200. If he chooses Kool Karate, he must pay an initial fee      Log On


   



Question 185491: Solve Problems Using Linear Systems
11. To join Karate Klub, David must pay a monthly fee of $25 and an initial fee of $200. If he chooses Kool Karate, he must pay an initial fee of only $100 but $35/month.
a) After how many months is the cost the same at either karate clubs?
(the asnwer is 10 months, but i dont know how to do it?)
b) If David plans to try karate for 6 months, which club should he join?
(the asnwer is Kool Karate, but i dont know how to do it?)
c) If David decideds to do karate for a year, which club should he join?
(the asnwer is Karate Klub, but i dont know how to do it?)

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
11. Start by writing the cost equation for each club.
C%5B1%5D+=+200%2B25x This is the cost for Karate Klub for x months.
C%5B2%5D+=+100+%2B35x This is the cost for Kool Karate for x months.
a) To find after how many months is the cost the same, set C%5B1%5D+=+C%5B2%5D and solve for x, the number of months.
C%5B1%5D+=+C%5B2%5D
200%2B25x+=+100%2B35x Subtract 25x from both sides.
200+=+100%2B10x Now subtract 100 from both sides.
100+=+10x Finally, divide both sides by 10.
highlight%2810+=+x%29
The cost will be the same in 10 months.
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b) To find which club is the better deal at 6 months, set x = 6 for both equations and see which one is less.
C%5B1%5D+=+200%2B25x Substitute x = 6.
C%5B1%5D+=+200%2B25%286%29
C%5B1%5D+=+200%2B150
highlight%28C%5B1%5D+=+350%29 Karate klub costs $350 for 6 months.
C%5B2%5D+=+100%2B35x Substitute x = 6.
C%5B2%5D+=+100%2B35%286%29
C%5B2%5D+=+100%2B210
highlight%28C%5B2%5D+=+310%29 Kool karate costs $310 for 6 months.
Kool Karate is less for 6 months.
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c) To find the best deal for 12 months, use part b) as a guide but set x = 12.
You can do this!