1. Tardigrade
  2. Question
  3. Mathematics
  4. Number of ways of selection of 4 letters of the word PERFECT is.

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Number of ways of selection of $4$ letters of the word PERFECT is____.

Permutations and Combinations

Solution:

$7$ letters
$P \rightarrow 1$
$E \rightarrow 2$
$R \rightarrow 1$
$F \rightarrow 1$
$C \rightarrow 1$
$T \rightarrow 1$
$2$ alike $+2$ diff. $=1 \times{ }^{5} C_{2}=10$
All $4$ different $={ }^{6} C_{4}=15$
Total $=15+10=25$