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Find sum of 7+10.5+14.........+84 |
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Answer» Answer: 1046.5 Step-by-step explanation: It is in series a=7 n=? d=3.5 l=a+(n-1) d 84=7+(n-1) 3.5 77=3.5(n-1) 22 =n-1 n=23 now we have to FIND sum if all terms sum=n/2(a+l) sum=23/2(7+84) sum=23*91/2 sum=23*45.5 sum=1046.5 |
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