In A.P. , 16th term is p , then find the sum of first 31 terms.

1.	In A.P. , 16th term is p , then find the sum of first 31 terms.
Answer» a16 = Pan = a+(n-1)da + 15d = P --------------(1)Sn = n/2[2a+(n-1)d]S31 = (31/2) [2a+30d]= (31/2) × 2 × (a+15d)= 31 × (a+15d)S31 = 31 P

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