In how many ways the letters of the word ‘REFERENCES’ can be arranged so that vowels remain together?

REFERENCES

Here? 4 vowels (4 E’s) and 6 consonants (2 R’s, 1 F, 1 N, 1 C and 1 S)

∴ Number of ways to arrange the letters so that vowels are together = 7!/ (4! × 2!)

⇒ 105