How many number of 4 digits can be formed with the digits 1,2,3,4,5 if repetition of digits is not allowed?  Choose the correct option:	A) 60	B) 120	C) 180	D) 240	E) 32
n = number of digits = 5   r = number of places to be filled up = 4   Required number = 5P4 = 5!/1! = 120   Answer is 120
<result>B</result>
How many number of 4 digits can be formed with the digits 1,2,3,4,5 if repetition of digits is not allowed?