Question

Find the sum of first 60 multiples of 3.

Answer 1

Lets first look at the first three terms of this series.

3, 6, 9

To find the sum of an arithmetic series, there are two separate formulas. The one we will use is sn=n2(2a+(n−1)d)

n, or the number of terms, is 30. d, the common difference, is 3. a, the first term in the series is 3.

Plugging these numbers into the formula, we get:

s30=302(2(3)+(29)3)

s30=15(6+87)

s30=15(93)

s30=1395

Answer 2

HOPE THIS HELPS U. ....