MCQ
51.
If ? = {a, b, c, d, e, f} then number of strings in ? of length 4 such that no symbol is used more than once in a string is
Correct Answer: B
Here string length is 4 so we create string of length 4 by 6 values firstly we arrange any value by 6 methods. Then Remaining numbers are 5 so we can arrange them by 5 methods then remaining numbers are 4 so we arrange them by 4 methods and then 3.Thus 6*5*4*3=360.