SOLUTION: Hi when bob bought 8 cds he was $28 short. When he bought 4 cds and 3 cassettes he had $17 left. if the cassettes cost $15 how much did he have ar first. thanks

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Question 1108918: Hi
when bob bought 8 cds he was $28 short. When he bought 4 cds and 3 cassettes he had $17 left.
if the cassettes cost $15 how much did he have ar first.
thanks

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
let x be the amount of money Bob has and y be the cost of a CD
:
1) x = 8y + 28
:
2) 4y + 3(15) = x - 17
:
use equation 1 and substitute for x in equation 2
:
4y + 45 = 8y + 28 - 17
:
4y = 34
:
y = 8.50
:
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Bob starts with 8(8.50) + 28 = $96
:
check answer in equation 2
:
4(8.50) + 3(15) = 96 - 17
:
34 + 45 = 96 - 17
:
79 = 79
:
answer checks
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