Exercise · ZW-PERMUTATIONS-WITH-REPETITION-005 · ★☆☆ Basic
Two red, two blue and two green flags, identical by colour, are placed in a row. In how many ways?
Choose one option.
Show answer
- C. \(90\)
Explanation
There are 6 flags in three types, each repeated twice: \(\dfrac{6!}{2!\,2!\,2!}=90\).
Review the concept: Permutations with repetition
The permutations with repetition of \(n\) objects, of which \(n_i\) are indistinguishable of a single type \(i\) (\(i=1,\dots,k\)), are their distinguishable arrangements in a row.
\[\dfrac{n!}{n_1!\,n_2!\cdots n_k!}\]
More practice problems: permutations with repetition
- ZW-PERMUTATIONS-WITH-REPETITION-001 How many distinct arrangements do the letters of the word AMAMA have?
- ZW-PERMUTATIONS-WITH-REPETITION-002 How many distinct arrangements does the word BANANA have?
- ZW-PERMUTATIONS-WITH-REPETITION-003 How many distinct arrangements does the word LEVEL have?
- ZW-PERMUTATIONS-WITH-REPETITION-004 A binary string of length 8 has exactly three ones. How many such strings are there?
- ZW-PERMUTATIONS-WITH-REPETITION-006 A robot goes from the bottom-left to the top-right corner of a grid with 4 steps right and 3 steps…
- ZW-PERMUTATIONS-WITH-REPETITION-007 How many distinct arrangements do the letters of MISSISSIPPI have?
- ZW-PERMUTATIONS-WITH-REPETITION-008 How many distinct arrangements of MATEMATICAS are there?
- ZW-PERMUTATIONS-WITH-REPETITION-009 How many distinct arrangements of MISSISSIPPI start with M?
← ZW-PERMUTATIONS-WITH-REPETITION-004 ZW-PERMUTATIONS-WITH-REPETITION-006 →