The number of different words that can be made from the letters of the word INTERMEDIATE,
The number of different words that can be made from the letters of the word INTERMEDIATE, such that two vowels never come together, is __________.
Number of letters in INTERMEDIATE is 12.
Number of vowels $(A, E, E, I, I, E)$ i.e is 6 .
Number of consonants (T T . R M N D) i.e is $6 .$
$\therefore$ Total words are $\frac{12 !}{3 ! 2 ! 2 !}$
Now, number of ways of arranging 6 consonants (2 alike) is
$\frac{6 !}{2 !}=6 \times 5 \times 4 \times 3$
= 360
There are 7 gaps in which 6 vowels can be arranged in 7P6 ways but 2 are alike of are kind and 3 of other kind
$\therefore$ Number of ways of arranging the vowels is ${ }^{7} P_{6} \times \frac{1}{3 ! 21}$
$=\frac{7 !}{1 !} \times \frac{1}{3 ! 2 !}$
$=\frac{7 !}{3 \times 2 \times 2}=\frac{7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}{3 \times 2 \times 2}$
$=20 \times 21$
$=420$
Hence, the total number of ways when the two vowels never come together is
360 × 420
= 151200