Q10 of 47 Page 1

How many terms of the A.P. 65, 60, 55,… be taken so that their sum is zero?

It is given in the question that,

Ist term, a = 65


Common difference, d = 60 – 65


= -5


Also, Sn = 0


We know that,




0 = n (135 – 5n)


∴ n = 0 or





As the number of terms cannot be zero therefore total number of terms will be 27


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