The sum of the first n terms of an arithmetic p... - JAMB Mathematics 2003 Question
The sum of the first n terms of an arithmetic progresssion is 252. If the first term is -16 and the last term is 72, find the number of terms in the series
A
6
B
7
C
8
D
9
correct option: d
\(S_n = 252, a = -16\hspace{1mm}and\hspace{1mm}l = 72\S_n = \frac{n}{2}(-16+72)\252 = \frac{n}{2}(-16+72)\n=\frac{504}{56}\n=9\)
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