6 Find the number of ways all 10 letters of the word COPENHAGEN can be arranged so that
- the vowels ( \(\mathrm { A } , \mathrm { E } , \mathrm { O }\) ) are together and the consonants ( \(\mathrm { C } , \mathrm { G } , \mathrm { H } , \mathrm { N } , \mathrm { P }\) ) are together, [3]
- the Es are not next to each other.
Four letters are selected from the 10 letters of the word COPENHAGEN.
- Find the number of different selections if the four letters must contain the same number of Es and Ns with at least one of each.