<PRE><B>Question 337866</B>
C=50+25t where t represents the number of months of operation of a cellular phone. 
How many months has the phone been in service if the total cost is $250.00? 
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Solve 50+25t = 250.00
25t = 200
t = 8
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What is the cost of the service after 18 months?
C(18) = 50+25*18 = $500
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Cheers,
Stan H. </PRE>