Question:
The number of ways to arrange the letters of the word CHEESE are
(a) 120
(b) 240
(c) 720
(d) 6
Solution:
(a) 120
Total number of arrangements of the letters of the word $\mathrm{CHEESE}=$ Number of arrangements of 6 things taken all at a time, of which 3 are of one kind $=\frac{6 !}{3 !}=120$