S = 3 + 6 + 9 + 12 + ... + 24
= 3 (1 + 2 + 3 + ... + 8)
= 3 x(8x9)/2
=108
Detailed Answer:
First 8 multiples of 3
3, 6, 9, 12, 15, 18, 21, 24
S = 3 + 6 + 9 + 12 + 15 + 18 + 21 + 24
These numbers are in A.P.
where a = 3, d = 3 and n = 8
∴Thus, sum of first 8 multiples of 3 of 108.
