16. The letters of the word MATHEMATICS are rearranged in such a way that the first four letters of the arrangement are ahl vowels. Find the total number of distinct arrangements that can be formed in this way.
(Note: The vowels of English language are A, E, I, O, U)
16. Answer: 15120

Total number of rearrangements $=\frac{4!}{2!} \times \frac{7!}{2!2!}=12 \times 1260=15120$.