A DJ found a music store that had a great collection of used CD's. he purshased 38 CD's for a total of $235. The purchase included CD's priced at either $5.00 or $8.00. How many CD's in each price category did the DJ buy?
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A DJ found a music store that had a great collection of used CD's. he purshased 38 CD's for a total of $235. The purchase included CD's priced at either $5.00 or $8.00. How many CD's in each price category did the DJ buy?
Call the number of CDs bought at $5.00 x. Call the number of CDs bought at $8.00 y. We know that the total cost was $235, so:Quote:
Originally Posted by wild_flowr69
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Additionally, we know that 38 CDs were bought, so:
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Two equations, two unknowns, so you can solve for x and y.
-Dan
Let me continue from topsquark's solution:
The equations
In the second equation solve for:
Substitute that into the first:
Now solve it,
Thus,
Thus,
Thus,