<PRE><B>Question 1118102</B>
 The sum of the first ten terms of a linear sequence is -60 and the sum of the first fifteen terms of the sequence is -165 find the 18th term of the sequence.
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10(a(1)+a(10))/2 = -60
15(a(1)+a(15))/2 = -165
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a(1)+a(10) = -12
a(1)+a(15) = -22
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a(10)-a(15) = 10
5d = 10
d = 2
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a(1) + 9d = -12
a(1) + 18 = -12
a(1) = -30
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Ans:: a(18) = -30 + 17*2 = -16
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Cheers,
Stan H.
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