Permutation and Combination
Q1. How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?
Q2. How many 4-digit numbers are there with no digit repeated?
Q3. How many 3-digit even numbers can be made using the digits 1, 2, 3, 4, 6, 7, if no digit is repeated?
Q4. Find the number of 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5, if no digit is repeated. How many of these will be even?
Ans: 120, 48
Q5. Find r if
(i)5Pr = 26Pr-1
(ii) 5Pr = 6Pr-1
Q6. How many words, with or without meaning, can be formed using all the letters of the word EQUATION, using each letter exactly once?
Q7. In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together?
Q8. If nC8 = nC2, find nC2.
Q9. Determine n if 2nC3:nC3 = 12: 1
Q10. Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour.
Q11. Determine the number of 5 card combinations out of a deck of 52 cards if there is exactly one ace in each combination.