Practice By Tag: Reordering the Letters of a Word

Question: 2014 Winter Midterm - 9

1 . How many strings can be obtained by rearranging the letters of the word

POOPERSCOOPER

(a)

${13 \choose 4}{9 \choose 3}{6 \choose 2}{4 \choose 2}$

(b)

${13 \choose 4}{9 \choose 2}{7 \choose 2}{5 \choose 3}$

(c)

$13!$

(d)

${13 \choose 1}{12 \choose 4}{8 \choose 2}{6 \choose 1}{5 \choose 2}{3 \choose 3}$