Exhaustive no. of cases =63 10 can appear on three dice either as distinct number as following (1,3,6);(1,4,5);(2,3,5) and each can occur in 3! ways.
Or 10 can appear on three dice as repeated digits as following (2,2,6),(2,4,4),(3,3,4) and each can occur in 2!3! ways. ∴ No. of favourable cases =3×3!+3×2!3!=27