Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed ?

Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4) = (7C₃ x 4C₂)
= { (7 x 6 x 5) / (3 x 2 x 1) } x { (4 x 3) / (2 x 1) } = 210.
Number of groups, each having 3 consonants and 2 vowels = 210.

Each group contains 5 letters.
Number of ways of arranging 5 letters among themselves = 5! = 5 x 4 x 3 x 2 x 1 = 120.

Required number of ways = (210 x 120) = 25200.