Question

How many words can be formed by taking three letters from the letters of the words "SERIES" ?

• A. 42
• B. 48
• C. 52
• D. 34

Answer 1

The correct option is A 42

Here S and E is repeated twice and R, I one time
Two cases are possible-
CASE 1:-All different words
$4C3\times 3!$
CASE 2:-Two same and one different
$2C1\times 3C1\times \frac{3!}{2!}$

answer-(CASE 1+CASE 2)=42
option (a) is correct