How many terms of Ap -15,-13,-11 are needed to make the sum -55 ? Explain the reason for double answer reason foe double answer..plz Share with your friends Share 2 Neha Sethi answered this Dear student The given AP is-15,-13,-11,...Here the first term,a=-15 and common difference,d=second term-first term=-13--15=-13+15=2Also, given sum of n terms=-55i.e. Sn=-55 Hence sum of 5 terms and 11 terms of the given AP is -55Note: Here we had a quadratic equation in n, so we will get 2 values of nand hence sum of 5 terms and 11 terms of the given AP is -55 Regards 1 View Full Answer Amit Shekhawat answered this Reason for double answer ....plz i know how to solve this question but dont know the reason for double answer.....plz the reason -1 Utkarsh answered this ap = -15 ,-13, -11 .... sn= -55 plz give full ap. -2