Question:
The number of words (with or without meaning) that can be formed from all the letters of the word "LETTER" in which vowels never come together is__________.
Solution:
For vowels not together
Number of ways to arrange $\mathrm{L}, \mathrm{T}, \mathrm{T}, \mathrm{R}=\frac{4 !}{2 !}$
Then put both $\mathrm{E}$ in 5 gaps formed in ${ }^{5} C_{2}$ ways.
$\therefore$ No. of ways $=\frac{4 !}{2 !} \cdot{ }^{5} C_{2}=120$
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.