Question

Out of the letters of the word INEFFECTIVE only 1422 four letter words can be formed.

• A. True
• B. False

Answer 1

The correct option is A True

Letters:-

C-1

E-3

F-2

I-2

N-1

T-1

V-1

ABCD type words : ${}^7{C}_4\times 4!$

ABCC type words : ${}^3{C}_1{\times }^6{C}_2\times \frac{4!}{2!}$

ABBB type words : $1{\times }^6{C}_1\times \frac{4!}{3!}$

AABB type words : ${}^3{C}_2\times \frac{4!}{2!\times 2!}$

Sum them over to get the total $=24+18+540+840=1422$