document.write( "Question 442740: A gallon of milk cost $1.99 five years ago, now it costs $2.89.\r
\n" ); document.write( "\n" ); document.write( "a. Write an exponential function.\r
\n" ); document.write( "\n" ); document.write( "b. what has been the annual rate of increase in the cost? \n" ); document.write( "
Algebra.Com's Answer #305426 by stanbon(75887)\"\" \"About 
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A gallon of milk cost $1.99 five years ago, now it costs $2.89.
\n" ); document.write( "a. Write an exponential function.
\n" ); document.write( "y = ab^x
\n" ); document.write( "----
\n" ); document.write( "Initial cost:
\n" ); document.write( "1.99 = a*b^0
\n" ); document.write( "a = 1.99
\n" ); document.write( "-----
\n" ); document.write( "After 5-yr cost:
\n" ); document.write( "2.89 = 1.99b^5
\n" ); document.write( "b^5 = 1.4523
\n" ); document.write( "b = 1.0775
\n" ); document.write( "-----------------
\n" ); document.write( "Equation:
\n" ); document.write( "y = 1.99*(1.0775)^t
\n" ); document.write( "===========================
\n" ); document.write( "
\n" ); document.write( "b. what has been the annual rate of increase in the cost?
\n" ); document.write( "Annual rate of increase = 0.0775 = 7.75%
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( " \n" ); document.write( "
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