- #1
iwan89
- 27
- 0
Homework Statement
A security code is formed by using three alphabet and four digits chosen from alphabet {a,b,c,d,e} and digits {1,2,3,4,5,6}. All digits and alphabets can only be used once. Find the number of different ways the security code can be formed if
(a) there is no restriction imposed (Answer :756000)
(b) It consists of at least two consonant (Answer: 529200)
Homework Equations
I used Permutation with restriction
The Attempt at a Solution
i tried the following. I am not sure whether the working is correct or not..
(a) 5P3(for alphabet) x 6P4(for digit) =21600.. but this seems wrong because my computation is based on the alphabet and digits must be togather
(b) I have no idea at all. I really need the idea from the first question :(