document.write( "Question 1155874: The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes). The remaining credit after 40 minutes of calls is $15.20, and the remaining credit after 72 minutes of calls is $11.36. What is the remaining credit after 86 minutes of calls? \n" ); document.write( "

Algebra.Com's Answer #778563 by ikleyn(52790) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "72 - 40 = 32 minutes of the phone call cost  15.20-11.36 = 3.84 dollars, giving the rate of   = 0.12 dollars per minute.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "So, after 86 minutes the amount on the card will be  15.20 - (86-40)*0.12 = 9.68 dollars.\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );