64
Subjective
How many words (with or without dictionary meaning) can be made from the letters of the word MONDAY, assuming that no letter is repeated, if
| Column I | Column II | ||
|---|---|---|---|
| (i) | 4 letters are used at a time | (a) | 720 |
| (ii) | All letters are used at a time | (b) | 240 |
| (iii) | All letters are used but the first is a vowel. | (c) | 360 |
Explanation
(i) 4 letters are used at a time $={ }^6 P_4=\frac{6!}{2!}=6 \times 5 \times 4 \times =360$
(ii) All letters used at a time $=6$ ! $=6 \times 5 \times 4 \times 3 \times 2 \times 1=720$
(iii) All letters used but first is vowel $=2 \times 5$ ! $=2 \times 5 \times 4 \times 3 \times 2 \times 1=240$