SOLUTION: At best buy Larry buys three CDs and three CDs for $108 from the sale rack. Kelly buys two CDs and one DVD from the same rack for $48. What is the price per CD and the price per DV

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Question 631939: At best buy Larry buys three CDs and three CDs for $108 from the sale rack. Kelly buys two CDs and one DVD from the same rack for $48. What is the price per CD and the price per DVD.?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = the cost of 1 CD
Let +b+ = the cost of 1 DVD
given:
(1) +3a+%2B+3b+=+108+
(2) +2a+%2B+1b+=+48+
Multiply both sides of (2) by +3+
and subtract (1) from (2)
(2) +6a+%2B+3b+=+144+
(1) +-3a+-+3b+=+-108+
+3a+=+36+
+a+=+12+
and
(2) +2a+%2B+1b+=+48+
(2) +2%2A12+%2B+1b+=+48+
(2) +24+%2B+b+=+48+
(2) +b+=+24+
The price per CD is $12 and
the price per DVD is $24
check:
(1) +3%2A12+%2B+3%2A24+=+108+
(1) +36+%2B+72+=+108+
(1) +108+=+108+
and
(2) +2%2A12+%2B+1%2A24+=+48+
(2) +24+%2B+24+=+48+
OK