Question 377435: I have no idea how to start on this problem,but I do know to solve by making equations for the number of magazines. here's the problem: james sold magazine subscriptions with three prices: $20, $27, and $18. He sold 6 fewer of the $20 subscriptions than of the $27 subscriptions and sold a total of 31 subscriptions. If his total sales amounted to $678, how many $18 subscriptions did James sell?. I'm really struggling in algebra right now, so thanks a =
Answer by robertb(5830)   (Show Source):
You can put this solution on YOUR website! a = # $20 mag,
b = # $27 mag,
c = # $18 mag.
Then a = b - 6,
a+b+c = 31, and
20a + 27b + 18c = 678.
Put eqn1 into eqn 2: b-6 + b + c = 31, or 2b + c = 37. Then c = 37 - 2b.
Put eqn1 into eqn 3: 20(b-6) + 27b + 18c = 678, or 47b + 18c = 798.
Thus we get 47b + 18(37 - 2b) = 798,
or 11b = 132, or b = 12, the number of $27 mags. c = 13, the number of $18 mags, and a = 6, the number of $20 mags.
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