Question

Find the Sum of the 15 multiples of 8?
_____QUALITY ANSWER NEEDED WITH WHOLE STEPS_____ NO SPAMMING__

Answer 1

The multiples of 8 are 8, 16, 24, 32… These are in an A.P., having first term as 8 and common difference as 8. Therefore, a = 8 d = 8 S15 = ? 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

Answer 2

$\huge \bold{hey \: there}$

The AP will be: 8, 16, 24, 32.....

Here, the common difference, d=8

➡First term, a=8

➡ Number of terms, n=15

We know that,

➡Sn=n/2(2a+(n-1)d)

Now,

➡S15=15/2[(2×8+(15-1)8]

➡S15=15/2(16+14×8)

➡S15=15/2(16+112)

➡S15=15/2×128

➡S15=15×64

➡S15=960

Answer:960