Question

What is the sum of the arithmetic sequence 3,9,15 if there are 36 terms?

Answer 1

a=3
d=6
n=36
s=n/2[2a+(n-1)d]

s=36/2[6+(35)6]
s=18[6+210]
s=18×216
s=3888.



hope it help you

Answer 2

Answer:

The sum is 3888

Step-by-step explanation:

The  arithmetic sequence is 3,9,15...... and there are 36 terms.

a = 3,

d = 9-3 = 6

n=36

The sum of n terms of an A.P is

$S_n=\frac{n}{2}(2a+(n-1)d)\\\\S_n=\frac{36}{2}(2\cdot3+(36-1)6)\\\\S_n=18(6+210)\\\\S_n=3888$

Hence, the sum is 3888