Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4)

= (7C3 x 4C2)

= 210.

So number of groups, each having 3 consonants and 2 vowels = 210.

Each group contains 5 letters and number of ways of arranging 5 letters among themselves

= 5!

= 120.

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

It is asked that to choose 3 consonants out of 7 not 4.