Question

There are 6 different letters and 6 correspondingly addressed envelopes. if the letters are randomly put in the envelopes, then what is the probability that exactly 5 letters go into the correctly addressed envelopes?

a) 0
b) ⅙
c) ½
d) ⅚​

Answer 1

Answer:

B - 1/6

Step-by-step explanation:

Let the letters be 1 , 2 , 3 , 4 , 5 , 6

Let their corresponding addressed envelopes be a , b , c , d , e , f

Sample space = S = { 1a , 1b , 1c , 1d , 1e , 1f , 2a , 2b , 2c , 2d , 2e , 2f , 3a , 3b , 3c , 3d , 3e , 3f , 4a , 4b , 4c , 4d , 4e , 4f , 5a , 5b , 5c , 5d , 5e , 5f , 6a , 6b , 6c , 6d , 6e , 6f }

n(S) = 36

Let A be the event that the letters go in their exact corresponding addressed envelopes

A = { 1a , 2b , 3c , 4d , 5e , 6f }

n(A) = 6

P(A) = n(A)/n(S) = 6/36 = 1/6

Hence , the answer is B - 1/6

Answer 2

The answer of this question is option is (b)1/6