How many terms of AP65 60 55 be taken to give the sun zero\xa0

1.	How many terms of AP65 60 55 be taken to give the sun zero\xa0
Answer» Ans. First term = 65Common Difference = -5Let number of terms required = nSn\xa0= 0=>\xa0{tex}{n\\over 2}[{2\\times 65 +(n-1)\\times (-5)}] =0{/tex}=> n[130 -5n +5] = 0=> n (135-5n)=0=> 135-5n = 0=> 135 = 5n=> n = 27number of terms = 27

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