Question

How many different arrangements of the letters in the word SCHOOL are there? .

Answer 1

Its a permutation with repetition sum.

The formula is : n! / (a! * b!)
where a = no. of Os = 2
b = no. of Ds = 2
n = total no. of letters in the word doodle = 6

Working: 6! / (2! * 2!)
= 6 x 5 x 4 x 3 x 2 x 1 / 2 x 1 x 2 x 1
= 180 Answer