Question

how many four letter words can be formed out of the PRECAUTION without repetition of any letter​

Answer 1

$\huge\green{\boxed{\bold{ Answer}}}$

Since none of the letters in the 10-letter long “logarithms” is a repeat:

P(10,4)=5040.

In other words, there 10 letters to choose for the first of the new 4-letter word, then 9 for the second, 8 for the third, and 7 for the fourth.

$10∗9∗8∗7=10!6!=10!(10–4)!=P(10,4)=504010∗9∗8∗7=10!6!=10!(10–4)!=P(10,4)=5040.$