document.write( "Question 174355: 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 30 minutes of calls is $15.46 and the monthly cost for 84 minutes is $20.32. What is the monthly cost for 54 minutes of calls? \n" ); document.write( "

Algebra.Com's Answer #129332 by jojo14344(1513) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "We'll interpolate the given data to get monthly cost for 54 minutes, which represented by $\"x\"$ :
\n" ); document.write( " $\"system%2830minutes=15.46%2C54minutes=x%2C84minutes=20.32%29\"$
\n" ); document.write( " $\"%2830-54%29%2F%2830-84%29=%2815.46-x%29%2F%2815.46-20.32%29\"$
\n" ); document.write( " $\"%28-24%29%2F%28-54%29=%2815.46-x%29%2F-4.86\"$ , cross multiply
\n" ); document.write( " $\"-24%28-4.86%29=-54%2815.46-x%29\"$
\n" ); document.write( " $\"116.64=-834.84%2B54x\"$ }
\n" ); document.write( " $\"116.64%2B834.34=54x\"$
\n" ); document.write( " $\"54x=951.48\"$ -------> $\"cross%2854%29x%2Fcross%2854%29=cross%28951.48%2917.62%2Fcross%2854%29\"$
\n" ); document.write( " $\"highlight%28x=17.62%29\"$ , Monthly cost for 54 minutes.
\n" ); document.write( "Thank you,
\n" ); document.write( "Jojo \n" ); document.write( "

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