Find sum of first 11 terms of an a.p. whose middle term is 60

1.	Find sum of first 11 terms of an a.p. whose middle term is 60
Answer» n=11(a1+a11) / 2 =60a1+a11=120sum of AP = n/2 (a1+a11)\xa0 = 11/2 x 120 = 660\xa0

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