Question
John bought 9 CDs. Some of them cost $12.75, and the rest cost $11.95. The total was $112.35. How many did he buy at each price?
Answers
R_scott
a + b = 9 ... 11.95 a + 11.95 b = 107.55
12.75 a + 11.95 b = 112.35
subtracting equations (to eliminate b) ... .80 a = 4.80
solve for a , then substitute back to find b
12.75 a + 11.95 b = 112.35
subtracting equations (to eliminate b) ... .80 a = 4.80
solve for a , then substitute back to find b