Question

Find the sum of first 8 multiples of 3.​

Answer 1

Answer:

108

Step-by-step explanation:

3+6+9+12+15+18+21+24 = 108. Using A.P,. Sn=n/2(2a+(n-1)d). Sn= 8/2[2(3)+(7)(3)] =108 [a=3,d=3,n=8].

Answer 2

Step-by-step explanation:

First 8 multiples of 3 are given as:

3, 6, 9,..........24

Here

a = 3, d = 3, n = 8,

$l = 24 \\ \because \: S_n \: = \frac{n}{2} \{a + l \} \\ \therefore \: S_8 \: = \frac{8}{2} \{3 + 24 \} \\ \therefore \: S_8 \: = 4 \times 27 \\ \therefore \: S_8 \: = 108$