document.write( "Question 1208236: Hi
\n" ); document.write( "David jogged for 5 days in a row. Each day he jogged 1.4km more than the day before. At the end of 5 days he jogged a total of 20.6km. How far did he jogged on the 5th day. \n" ); document.write( "
Algebra.Com's Answer #846756 by MathTherapy(10553)\"\" \"About 
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document.write( "Hi\r\n" );
document.write( "David jogged for 5 days in a row. Each day he jogged 1.4km more than the day before. At the end of 5 days\r\n" );
document.write( "he jogged a total of 20.6km. How far did he jogged on the 5th day. \r\n" );
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document.write( "The MIDDLE day of the 5-day period is the \"matrix%281%2C6%2C+%285+%2B+1%29%2F2%2C+%22=%22%2C+6%2F2%2C+%22=%22%2C+3%5E%28rd%29%2C+day%29\"\r\n" );
document.write( "On the MIDDLE or 3rd day, he jogged the AVERAGE/MEAN number of miles, or \"matrix%281%2C4%2C+20.6%2F5%2C+%22=%22%2C+4.12%2C+miles%29\"\r\n" );
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document.write( "He jogged 4.12 miles on the 3rd day, and consistently jogged 1.4 miles greater than previous days. \r\n" );
document.write( "So, on the 5th day (2 days after the 3rd day), he jogged 4.12 + 2(1.4) = 4.12 + 2.8 = 6.92 miles.\r\n" );
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document.write( "OR.\r\n" );
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document.write( "This is an AP/AS (Arithmetic Progression/Arithmetic Sequence) that the following SUM of an AP formula\r\n" );
document.write( "can be used. \"matrix%281%2C3%2C+S%5Bn%5D%2C+%22=%22%2C+%28n%2F2%29%282a%5B1%5D+%2B+%28n+-+1%29d%29%29\", with: Sn = Sum of the sequence (20.6, in this case)\r\n" );
document.write( "                                               n = Number of terms (5,in this case)\r\n" );
document.write( "                                              a1 = The 1st term of the sequence (UNKNOWN, in this case)\r\n" );
document.write( "                                               d = Common difference (1.4, in this case)\r\n" );
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document.write( "          \"matrix%281%2C3%2C+20.6%2C+%22=%22%2C+%285%2F2%29%282a%5B1%5D+%2B+%285+-+1%291.4%29%29\" ---- Substituting 20.6 for Sn, 5 for n, and 1.4 for d\r\n" );
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document.write( "           4.12 = a1 + 2.8\r\n" );
document.write( "     4.12 - 2.8 = a1\r\n" );
document.write( "           1.32 = a1 (First term of this AP/AS)\r\n" );
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document.write( "On the 5th day, he jogged 1.32 + (5 - 1)(1.4) = 1.32 + 4(1.4) = 1.32 + 5.6 = 6.92 miles.\r\n" );
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document.write( "To find the 5th term, you could've also used the following formula for a specific tern of an\r\n" );
document.write( "AP/AS: \"matrix%281%2C3%2C+a%5Bn%5D%2C+%22=%22%2C+a%5B1%5D+%2B+%28n+-+1%29d%29\", with: an = a Specific tern of the sequence (UNKNOWN, in this case)\r\n" );
document.write( "                                  n = Term Number being sought (5, in this case)\r\n" );
document.write( "                                 a1 = The 1st term of the sequence (1.32, in this case)\r\n" );
document.write( "                                  d = This sequence's common difference (1.4, in this case)\r\n" );
document.write( "SELAH!!
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