Question

Find the sum of first 100 even natural no divisible by 6

Answer 1

6 , 12 , 18 , 24 , 30 , 36 , 42 , 48 , 54 , 60 ,66, 72 , 78 , 84 , 90 and 96

Answer 2

Given condition can be written in form of an A.P.

i.e.   6+12+18+24+30.........up to first hundred terms.

Here,    a=6,   d=6,  n=100

.'. S(100)= 100/2 [2 x 6 + (100-1)6]    {'.' S(n) = n/2 [2a+(n-1)d] }

             = 50 [12 + 594]

             = 30300