Permutations and Combinations questions
785 published questions with worked solutions.
- If 26!=n8^k, where k and n are positive integers, then what is the maximum value of k?
- How many four-digit natural numbers are there such that all of the digits are even?
- Four digit numbers are formed by using the digits 1, 2, 3, 5 without repetition of digits. How many of them are divisible by 4?
- What is the number of different matrices, each having 4 entries that can be formed using 1, 2, 3, 4 (repetition is allowed)?
- How many 4-digit numbers are there having all digits as odd?
- In how many ways can the letters of the word INDIA be permutated such that in each combination, vowels should occupy odd...
- The letters of the word EQUATION are arranged in such a way that all vowels as well as consonants are together. How many such...
- In how many ways can a student choose (n-2) courses out of n courses if 2 courses are compulsory (n>4)?
- Three perfect dice D_1, D_2 and D_3 are rolled. Let x, y and z represent the numbers on D_1, D_2 and D_3 respectively. What is...
- In how many ways can the letters of the word DELHI be arranged keeping the positions of vowels and consonants unchanged?
- What is the number of positive integer solutions of x+y+z=5?
- If the number of selections of r as well as (n+r) things from 5n different things are equal, then what is the value of r?
- What is the number of selections of at most 3 things from 6 different things?
- Let y=x! and z=(2x)!. If (z/y)=120, then what is the value of (3x)!?
- Let n be a natural number. The number of consecutive zeros at the end of the expansion of n! is exactly 2. How many values of n...
- How many 4-digit numbers that are divisible by 4 can be formed using the digits 1, 2, 3 and 4 (repetition of digits is not...
- What is the greatest value of r satisfying the inequality ^ 15 C_ r+1 >2 ^ 15 C_r?
- If n= ^mC_2 then what is ^nC_2 equal to?
- How many numbers greater than 1000 can be formed using the digits 0, 1, 2 and 3 (repetition of digits is not allowed)?
- 4-digit numbers are formed with 1, 2, 3 and 4. What is the number of the 4-digit numbers in which at least one digit is repeated?
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