Question

How many permutations of { a,b,c,d,e,f,g} end with ab?

Answer 1

we can permutate BA, C, D, E, FGH. Hence, there are 5!= 120 permutations of the letters ABCDEFGH that contain the strings BA and FGH. (d) Similar to part (c), we can permutate AB, C, DE, F, GH.

Answer 2

Given:

{${a,b,c,d,e,f,g}$}

To find:

The number of permutations of {${a,b,c,d,e,f,g}$} end with ab

Step-by-step explanation:

There are $7$ letters given in the set. It is given that every permutation should end with ab.

Therefore, the permutation can be formed from remaining $5$ letters.

$5!\;=\;5\times4\times3\times2\times1$

⇒ $5!\;=\;120$ ways

Answer:

The number of permutations {${a,b,c,d,e,f,g}$} end with ab are $120$