In how many different ways can the letters of the word SMART be arranged?
A
25
B
60
C
180
D
200
E
None of these
Correct Answer: None of these
The given word contains 5 letters, all different.∴ Required number of ways
$$\eqalign{ & = {}^5{P_5} \cr & = 5! \cr & = \left( {5 \times 4 \times 3 \times 2 \times 1} \right) \cr & = 120 \cr} $$