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

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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) (Show Source):
You can put this solution on YOUR website!
11. Start by writing the cost equation for each club.
This is the cost for Karate Klub for x months.
This is the cost for Kool Karate for x months.
a) To find after how many months is the cost the same, set and solve for x, the number of months.

Subtract 25x from both sides.
Now subtract 100 from both sides.
Finally, divide both sides by 10.

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.
Substitute x = 6.

Karate klub costs $350 for 6 months.
Substitute x = 6.

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!