document.write( "Question 1148592: The monthly cost (in dollars) of a long-distance phone plan is a linear function of the total calling time (in minutes). The monthly cost for 36 minutes of calls is $17.53 and the monthly cost for 75 minutes is $21.82. What is the monthly cost for 59 minutes of calls?
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Algebra.Com's Answer #769951 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
You are given 2 points on the straight line
\n" ); document.write( "( 36, 17.53 )
\n" ); document.write( "( 75, 21.82 )
\n" ); document.write( "Let $\"+C+\"$ = Monthly cost of plan
\n" ); document.write( "Let $\"+t+\"$ = calling time in minutes
\n" ); document.write( "You can use the general point-slope formula
\n" ); document.write( " $\"+%28+C+-+17.53+%29+%2F+%28++t+-+36+%29+=+%28+21.82+-+17.53+%29+%2F+%28+75+-+36+%29+\"$
\n" ); document.write( " $\"+%28+C+-+17.53+%29+%2F+%28++t+-+36+%29+=+4.29+%2F+39+\"$
\n" ); document.write( " $\"+%28+C+-+17.53+%29+%2F+%28++t+-+36+%29+=+.11+\"$
\n" ); document.write( " $\"+C+-+17.53+=+.11t+-+3.96+\"$
\n" ); document.write( " $\"+C+=+.11t+%2B+13.57+\"$
\n" ); document.write( "-----------------------------
\n" ); document.write( " $\"+t+=+59+\"$ min
\n" ); document.write( " $\"+C+=+.11%2A59+%2B+13.57+\"$
\n" ); document.write( " $\"+C+=+6.49+%2B+13.57+\"$
\n" ); document.write( " $\"+C+=+20.06+\"$
\n" ); document.write( "$20.06 per month
\n" ); document.write( "Get a 2nd opinion if needed\r
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