Question

Find the number of ways so that letters of the word HISTORY can be arranged as end in ST

Answer 1

In the word 'HISTORY', the number of letters is n = 7.

Words end in ST:

Since the words end in ST, therefore we have to arrange only 5 positions from the remaining 5 letters.

This can be done in ⁵P₅ ways.

Hence, the total number of words end in ST

= ⁵P₅

= 5!

= 5 × 4 × 3 × 2 × 1

= 120