Solution:
8, 16, 24, 32… are the multiples of 8
This series creates an A.P., with the first term being 8 and the common difference being 8.
As a result, a = 8
d = 8
S15 = ?
Using the formula of sum of nth term, we know,
Sn = n/2 [2a+(n-1)d]
S15 = 15/2 [2(8) + (15-1)8]
= 15/2[6 +(14)(8)]
= 15/2[16 +112]
= 15(128)/2
= 15 × 64
= 960