Question 711986
Determine the number of terms in the following arithmetic sequence: 
315, 304, 293, ... , 18
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a = 315
d = 304-315 = -11
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Solve for "n":
a(n) = a + (n-1)d
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18 = 315 + (n-1)(-11)
-297 = (n-1)(-11)
n-1 = (-297/-11)
n-1 = 27
n = 28 (# of terms)
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Cheers,
Stan H.