Question

The number of combinations for the word MORADABAD taking 4 ata a time​

Answer 1

Step-by-step explanation:

MORADABAD

1M;1O;1R;3A;2D;1B

case i) all four letters are different

6

C

4

×4!=

2!

6×5

×4×3×2

case ii) 2 alike of one kind & 2 alike other kind

2

C

2

×

2!2!

4!

⇒

2!×2!

4×3×2!

=6

case iii) 2 alike of one kind of 2 are different

2

C

1

×

5

C

2

×

2!

4!

⇒

2

2×5×4

×

2!

4×5×2!

case iv) Three alike of one kind & one different

1

C

1

×

5

C

1

×

3!1!

4!

⇒5×4=20

Total number of 4 letter of words

=360+6+240+20

=626