document.write( "Question 550032: Customers of a phone company can choose between two service plans for long distance calls. The first plan has a $22 monthly fee and charges an additional $0.13 for each minute of calls. The second plan has an $8 monthly fee and charges an additional $0.18 for each minute of calls. For how many minutes of calls will the costs of the two plans be equal? \n" ); document.write( "

Algebra.Com's Answer #358351 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"t\"$ = time of calls in minutes
\n" ); document.write( "Let $\"C\"$ = cost of plan
\n" ); document.write( "Let the period of each plan = 1 month
\n" ); document.write( "1st plan:
\n" ); document.write( " $\"+C+=+22+%2B+.13t+\"$
\n" ); document.write( "2nd plan:
\n" ); document.write( " $\"+C+=+8+%2B+.18t+\"$
\n" ); document.write( "---------------
\n" ); document.write( "Set the costs equal to each other
\n" ); document.write( " $\"+22+%2B+.13t+=+8+%2B+.18t+\"$
\n" ); document.write( " $\"+.18t+-+.13t+=+22+-+8+\"$
\n" ); document.write( " $\"+.05t+=+14+\"$
\n" ); document.write( " $\"+t+=+280+\"$
\n" ); document.write( "When call minutes = 280, the cost of the plans are equal
\n" ); document.write( "check answer:
\n" ); document.write( " $\"+C+=+22+%2B+.13%2A280+\"$
\n" ); document.write( " $\"+C+=+22+%2B+36.4+\"$
\n" ); document.write( " $\"+C+=+58.4+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+C+=+8+%2B+.18%2A280+\"$
\n" ); document.write( " $\"+C+=+8+%2B+50.4+\"$
\n" ); document.write( " $\"+C+=+58.4+\"$
\n" ); document.write( "OK \n" ); document.write( "

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