Answer: 11
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Work Shown:
c = number of chairs
1 chair costs $12, so buying c of them costs 12c dollars.
She spent $108 total, meaning the equation is 12c = 108. That solves to c = 9 when you divide both sides by 12.
So that means she paid for 9 chairs. We're told that she gets a free chair for every 4 she buys. Since 9/4 = 2.25, it tells us that buying two batches of four chairs will get her 2 bonus chairs free of charge. Therefore, the total amount of chairs she receives is 9+2 = 11