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how many terms of the arithmetic progression 25,22,19 are needed to give the sum of 116 also find the last term. |
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Answer» Answer: We KNOW the formula that sn= n/2 [2a +(n-1) d] Sn= 116 a= 25 d=22-25 =-3 n=? 116= n/2 [2×25 +(n-1) -3] 232= n[50-3n+3] 232=53n-3n^2 3n^2-53n+232= 0 3n^2-24n-29n+232=0 3n(n-8)-29(n-8)=0 (n-8) (3n-29) =0 n=8 Hence the number of terms of AP is 8. Hope it helps. Thanks Mark it as brainliest. |
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