Question

Please help! Consider the sequence {20, 17, 14, 11, 8, 5, 2...}.

Answer 1

Answer:

c.) 38

Step-by-step explanation:

$\sum\limits_{n=3}^6 a_n$   means "summation of the all the elements starting from the 3rd element to the 6th element".

The 3rd element in the series is 14, and the 6th element is 5; we have to add these and all the elements between them together.

∴    $\sum\limits_{n=3}^6 a_n$    =  14 + 11 + 8 + 5

                   = 38