Question

Find the sum of first 10 multiples of 6?

Answer 1

$1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10(6) \\ 55(6) = 330$

Answer 2

Answer:

Step-by-step explanation:

Ap = 6 , 12 , 18 ....

1st term, a = 6 , difference, d = 12-6=6

A*10 = 6+(10-1)6

= 6+(9)6 = 6+54 = 60

S*10 = n/2 [a+an]

= 10/2(6+60)

= 5×66 = 330