Question

Can any one help me to solve this problem. Pls

Answer 1

Two digits no. divisible by 3 are

15 , 21, 27, 33, 39, 45, 51, 57 , 63, 69, 75, 81, 87, 93, 99

So sum is given by

Sn = n/2(a + l)

S15 = 15/2 (15 + 99)

= (15 × 114)/2

= 855


Thanks