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2 votes
What is the sum of the series?

20
sigma (5-n)
n-1

A-220
B-110
C-95
D110

User Faheem
by
8.3k points

1 Answer

6 votes

\bf \sum\limits_(n=1)^(20)~5-n\implies \sum\limits_(n=1)^(20)~5~~-~~\sum\limits_(n=1)^(20)~n\implies 20\cdot 5~~-~~\cfrac{20(20+1)}{2} \\\\\\ 100~~-~~210\implies -110
User Nistor Alexandru
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8.2k points