0606 P21 - Jun 2018 - Q3 - 5 marks
8446
A 7-character password is to be selected from the 12 characters shown in the table. Each character may be used only once.
| Characters | ||||
|---|---|---|---|---|
| Upper-case letters | A | B | C | D |
| Lower-case letters | e | f | g | h |
| Digits | 1 | 2 | 3 | 4 |
Find the number of different passwords
(i) if there are no restrictions,
(ii) that start with a digit,
(iii) that contain 4 upper-case letters and 3 lower-case letters such that all the upper-case letters are together and all the lower-case letters are together.
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