Question

find the sum of first 8 multiples of 3​

Answer 1

In this case, we have to apply the formula[n/2{2a+(n-1)d}] of arithmetic progression.

Here,

‘a’ is the first term i. e 3.

‘d’ is the common difference (difference term and the term before it) i. e 3

‘n’ is the number of terms i. e 8

Now applying the formula :

[n/2{2a+(n-1)d}]

=[8/2{2*3+(8-1)3}]

=4 {6+(7*3)}

=4(6+21)

=4*27

= 108

Answer 2

$<b>First 8 multiples of 3 = 3,6,9,12,15,18,21,24 Their sum = 3 + 6 + 9 + 12 + 15 + 18 + 21 + 24 = 108 Answer$