Question

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

Answer 1

as formula says:

sum = $n *\frac{ a_{1} + a_{n} }{2}$

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

Answer 2

Answer:

240

Step-by-step explanation:

Hope this helps! :)