Question

what is the sum of the series?
20
sigma (5-n)
n-1

A-220
B-110
C-95
D110

Answer 1

$\bf \sum\limits_{n=1}^{20}~5-n\implies \sum\limits_{n=1}^{20}~5~~-~~\sum\limits_{n=1}^{20}~n\implies 20\cdot 5~~-~~\cfrac{20(20+1)}{2} \\\\\\ 100~~-~~210\implies -110$

Answer 2

Answer:

B. -110

Step-by-step explanation: