Question

What is the sum of the series?​

Answer 1

45

Explanation:

Since the values are relatively small substitute i = 1 to 5 into 3i and sum

(3 × 1) + (3 × 2) + (3 × 3) + (3 × 4) + (3 × 5)

= 3 + 6 + 9 + 12 + 15

= 45