1.

n letters to each of which corresponds on addressed envelope are placed in the envelop at random. Then the probability that n letter is placed in the right envelope, will be:

A. \[\frac{1}{1!}-\frac{1}{2!}+\frac{1}{3!}-\frac{1}{4!}+...{{(-1)}^{n}}\frac{1}{n!}\]
B. \[\frac{1}{2!}+\frac{1}{3!}+\frac{1}{4!}-\frac{1}{5!}+...\frac{1}{n!}\]
C. \[\frac{1}{2!}-\frac{1}{3!}+\frac{1}{4!}-\frac{1}{5!}+...{{(-1)}^{n}}\frac{1}{n!}\]
D. None of these
Answer» D. None of these


Discussion

No Comment Found

Related MCQs