document.write( "Question 853253: The numbers of seats in the first 12 rows of a high school auditorium form an arithmetic sequence. The first row has nine seats. The second row has 11 seats.\r
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\n" ); document.write( "c). How many seats are in the 12th row? \n" ); document.write( "
Algebra.Com's Answer #513968 by ramkikk66(644)\"\" \"About 
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document.write( "The numbers of seats in the first 12 rows of a high school auditorium form an arithmetic sequence. The first row has nine seats. The second row has 11 seats. \r\n" );
document.write( "a). Write a recursive formula to represent the sequence.\r\n" );
document.write( "b). Write an explicit formula to represent the sequence.\r\n" );
document.write( "c). How many seats are in the 12th row?\r\n" );
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document.write( "Ans:\r\n" );
document.write( "a) Recursive formula for the number of seats in n'th row is: S(n) = S(n-1) + 2\r\n" );
document.write( "b) Explicit formula is that of an arithmetic progression. If a is the first term, \r\n" );
document.write( "and d is the common difference, the nth term is given by a + (n - 1)*d\r\n" );
document.write( "Here a is 9 and d is 2. Hence the number of seats in the n'th row will be\r\n" );
document.write( "9 + 2*(n - 1)\r\n" );
document.write( "c) Applying the above formula, number of seats in 12th row (i.e. n = 12)\r\n" );
document.write( "is 9 + 2*(12 - 1) = 9 + 2*11 = 31 seats.\r\n" );
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document.write( "Hope this helps :)\r\n" );
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