The number of permutations of the 26 letters of the English alphabet that do not contain any of the strings fish, rat, or bird is 402619359782336797900800000
Let

Then

Note that since
, 
But since
, 
and
, 
Since

where 
and

What we are looking for is the number of permutations of the 26 letters of the alphabet that do not contain the strings fish, rat or bird, or

This link contains another solved problem on permutations:
brainly.com/question/7951365
Answer:
<em> 3 + 3x = 45 ; x = 14 </em>
Step-by-step explanation:
45 = 3x + 3 ⇒ <em>x = 14</em>
Answer:
Step-by-step explanation:
4/15×6/14= 0.1142
Answer:
1002
Step-by-step explanation:
171x6=1026
171×2=342
1026-342=684
684+318=1002