Question

How many three-letter "words" can be made from 7 different letters "FGHIJKL" if...

a) Repetition of letters is allowed?
b) Repetition of letters is not allowed?

Answer 1

343

Explanation:

How many three-letter ”words” can be made from 7 letters FGHIJKL” if repetition of letters (a) is allowed? (b) is not allowed? Solution: (a) If repetition is allowed each letter can be any of the 7. So number ways is 7 × 7 × 7=73 = 343

Answer 2

Answer: See below

Explanation:

Given:

The letters FGHIJKL

To find:

The number of three letter words can be formed if repetition is allowed (or) if repetition is not allowed

`$$(a) If repetition is allowed:Total no of three letter words can be made$$=7_(C 1) x 7_(C 1) x 7_(C 1)=7^(3)=343$$(b) If repetitions is not allowed :Total no of three letter words can be made without repetition is $$\begin{gathered}=7_(C 1) * 6_(C 1) * 5_(C 1) \\=7 x 6 * 5=210\end{gathered}$$`