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,

S_n = 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