Question

Find the sum of the arithmetic sequence. 15, 17, 19, 21, ..., 33

Answer 1

240

Explanation:

Hope this helps! :)

Answer 2

as formula says:

sum =
`n *( a_(1) + a_(n) )/(2)`

in our case n = 10, a1 = 15 and An = 33 so the answer will be:

sum = 10 * (33 + 15)/2 = 10 * 48 / 2 = 10 * 24 = 240