exterior house paint colors
translate.google.com.hk
Related Articles
Trending Articles
Question: A wildlife conservation network uses a 5-letter code for unique identification of species monitoring drones, where each letter is either C or D, and the code must contain at least two consecutive identical letters. How many valid codes are possible?
Each position has 2 choices (C or D), so:
Codes with No Two Consecutive Identical Letters (Alternating):
These are strictly alternating: e.g., CDCDC or DCDCD.
Codes with At Least Two Consecutive Identical Letters:
Subtract the non-alternating (invalid for our condition) from total:
At a biodiversity summit, 5 scientists and 3 local stewards are to be seated around a circular table. If the stewards insist on sitting together, how many distinct seating arrangements are possible, treating rotations as identical?
Since its a circular arrangement and rotations are considered the same, we fix one position to eliminate rotational symmetry.
They must sit together, so consider them as a single super unit.
Now we have: 5 scientists + 1 block = 6 units to arrange in a circle.