document.write( "Question 1106201: A cassette shop charges Rupees 15 for renting a video cassette for the first day. It charges rupees 2 extra for every additional day. What will be the algebraic expression for the amount that Sara would pay. If she rents a video cassette for n days \n" ); document.write( "
Algebra.Com's Answer #721234 by ikleyn(52914)\"\" \"About 
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\n" ); document.write( "I read and understand the condition differently:\r
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document.write( "    In the first day the shop charges 15 rupees, in the 2-nd day it charges 15+2 = 17 rupees, \r\n" );
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document.write( "    in the third day it charges 17+2 = 19 rupees . . . and so on.\r\n" );
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document.write( "    What is a bill after \"n\" days ?\r\n" );
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document.write( "So, it is about finding the sum of the arithmetic progression\r\n" );
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document.write( "    15, 17, 19, . . . 15+2(n-1).\r\n" );
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document.write( "The first term is 15, the common difference is 2, and the number of terms = number of days = n.\r\n" );
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document.write( "The answer is: the balance, i.e. the sum of n terms, is \"S%5Bn%5D\" = \"%28a%5B1%5D%2Bd%2A%28n-1%29%2F2%29%2An\" = \"%2815+%2B+%282%28n-1%29%29%2F2%29%2An\" = \"%2815+%2B+%28n-1%29%29%2An\" = (14+n)*n.\r\n" );
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\n" ); document.write( "On arithmetic progressions, see the lessons in this site:\r
\n" ); document.write( "\n" ); document.write( "    - Arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - The proofs of the formulas for arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Problems on arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Word problems on arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Mathematical induction and arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - One characteristic property of arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Solved problems on arithmetic progressions \r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Arithmetic progressions\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "into your archive and use when it is needed.\r
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