Counting methods and probability theories 1. A scrambled word game challenges th
ID: 3141194 • Letter: C
Question
Counting methods and probability theories
1. A scrambled word game challenges the user to create three-letter words (nonsense words included) from five different letters. If a letter cannot be used in a word more than once, how many potential words can be created?
2. How many license plates containing seven characters can be created from letters and numbers if the first two characters must be uppercase letters and the last five characters must be digits from 0 to 9? Repetition of numbers is allowed. Repetition of letters is not allowed.
3. How many ways can you rank your top three movies from the 38 movies on your laptop?
Please show work.
Explanation / Answer
Solution:
1. Since we are having 5 different letters and we have to chose 3 letters word without any repeatition
therefore
first can be chosen = 5 ways
second can be chosen = 4 ways
and last can be chosen = 3 ways
potential words can be created = 5 x 4 x 3 = 60 ways
(2)
first letter can be selected for 7 th place = 26 ways
and second letter can be selected for 6 th place = 25 ways
and selection number for reamining 5 places = 10 x 9 x 8 x 7 x6
license plates containing seven characters can be created = 25 x 26 x 10 x9x8x7x6
= 19656000
(3)
Let first movie can be chosen form 38 movies = 38 ways
and second movie = 37 ways
and third movie = 36 ways
therefore
number of ways you can rank your top three movies from the 38 movies = 38 x 37 x36
= 50616 ways