Question

3.
How many two letter words can be formed
using letters from the word SPACE, when
repetition of letters (i) is allowed, (ii) is not
allowed?​

Answer 1

Answer:

I) 25

Ii) 20

Step-by-step explanation:

for repetition allowed:5×5=25

for not allowed:5×4=20

Answer 2

1) Two letter words formed by repetition of letters is 16.

2) Two letter words formed without repetition of letters is 12.

Step-by-step explanation:

The given word is SPACE.

We have to find the number of two letter words when

1) Repetition is allowed

     As we have to form a two letter word

     1st place can be filled in 4 ways and

     2nd place can also be filled in 4 ways as repetition of words is allowed

Hence two places can be filled in $4\times4 =16$ ways

∴The required number of two letter words with repetition is 16.

2) Repetition is not allowed

      As we have to form a two letter word,

   the 1st place can be filled in 4 ways and

   the 2nd place can be filled in 3 ways as repetition of words is not allowed.

   Hence two places can be filled in $4\times3 = 12$ ways

∴ The required number of two letter words without repetition is 12.