SOLUTION: During the week a man used 500 minutes of internet time and 100 minutes of phone time; his bill was $88. The next week he used 400 minutes of internet time and 150 minutes of ph

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Question 84104: During the week a man used 500 minutes of internet time and 100 minutes of phone time; his bill was $88. The next week he used 400 minutes of internet time and 150 minutes of phone time; his bill was $76. Find the cost per minute for the internet service. You must state your 2 equations and then your answers.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
t%5Bi%5D = time on the internet in minutes
t%5Bp%5D = time on the phone in minutes
r%5Bi%5D = rate for internet use in dollars/minute
r%5Bp%5D = rate for phone use in dollars/minute
b = total bill for phone and internet
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b+=+t%5Bi%5D%2Ar%5Bi%5D+%2B+t%5Bp%5D%2Ar%5Bp%5D
500%2Ar%5Bi%5D+%2B+100%2Ar%5Bp%5D+=+88
400%2Ar%5Bi%5D+%2B+150%2Ar%5Bp%5D+=+76
Multiply the 1st equation by 3 and the 2nd by 2
1500%2Ar%5Bi%5D+%2B+300%2Ar%5Bp%5D+=+264
800%2Ar%5Bi%5D+%2B+300%2Ar%5Bp%5D+=+152
subtract the 2nd from the 1st
700%2Ar%5Bi%5D+=+112
r%5B1%5D+=+.16
So, the rate for internet use is 16 cents/minute