Question:
If the sum of an arithmetic sequence is 476, the last term is 20, and the number of terms is 17, what is the first term?
A32
B34
C36
D38
Answer:
C. 36
Explanation:
Sn=n/2(T1+Tn) 476=17/2(T1+20) 476×2/17 =T1+20 56=T1+20 T1=36
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