Find the sum of 7,10 1/2,14 . .. 84

1.	Find the sum of 7,10 1/2,14 . .. 84
Answer» n=23Sn=1046 1/2 Here, a = 7, d = 3.5 and last term = 84Number of terms can be calculated as follows;{tex}a_n = a+(n−1)d{/tex}Or, {tex}84 =7+(n−1)3.5{/tex}Or, {tex}(n−1)3.5 = 84−7{/tex}Or, {tex}n−1 = 77 /3.5 = 22{/tex}Or, {tex}n = 23{/tex}

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