Question

Find the sum o first five multiples of 2.

Answer 1

2+4+6+8+10=30
30 is the answer

Answer 2

First multiple:4 a:4,n=5

Last multiple:10 l=10

D=2

Sn=n/2 [2a+(n-1)d]

=5/2 [2×4+(5-1)2]

So,5/2×16

=5×8

40 (ANSWER)