Question

4 letters are typed, without repetition. What is the probability that all 4 will be vowels? Write your answer as a percent. Round your answer to three decimal places.

Answer 1

Assuming you count 5 vowels, and no repetition ,
prob(4 vowels in 4 tries)
= (5/26)(4/25)(3/24)(2/23) = .....

Answer 2

(5 C 4 * 21 C 0)/26 C 4= 3.344481605E-4 = 0.0003344481605
*100= 0.03344481605% = 0.033%

C: Combinations on Ti-84 Plus Calculator

Hope this helps =D