CBSE CLASS XI
Permutations & Combinations
Q.4. Determine n if : 2nC3 : nC3 = 11 : 1
Q. 5. In how many ways can 4 red, 3 yellow and 2 green discs can be arranged in a row if the discs of the same colour are indistinguishable.
Q.6. Given 5 flags of different colours, how many different signals can be generated if each signal requires the use of two flags, one below the other?
Q.7. How many 4 –digit numbers are there with no digits repeated.
Q.8. How many three-digit numbers can be formed without using the digits 0,2,3,4,5 and 6?
Q.9. How many numbers are there between 100 and 1000 in which all the digits are distinct?
Q.10. How many numbers are their between 100 and 1000 such that 7 is in the unit’s place.
Q.11. How many numbers greater than 1000, but not greater than 4000 can be formed with the digits 0,1,2,3,4 if: (i) repetition of digits is allowed?
Q.12. How many three digit odd numbers can be formed by using the digits 1,2,3,4,5,6 if:
Q.13. How many four-digit numbers can be formed with the digits 3,5,7,8,9 which are greater than 7000, if repetition of digits is not allowed?
Q.14. How many numbers greater than 1000000 can be formed by using the digits 1,2,0,2,4,2,4?
Q.15. How many odd numbers less than 1000 can be formed by using the digits 0,3,5,7 when repetition of digits is not allowed?
Q.16. How many different numbers of six digits can be formed from the digits 3,1,7,0,9,5 when repetition of digits is not allowed?
Q.17. How many four digit different numbers, greater than 5000 can be formed with the digits 1, 2, 5, 9, 0 when repetition of digits is not allowed?
Q.18.. How many 6-digit telephone numbers can be constructed with digits 0,1,2,3,4,5,6,7,8,9 if each number starts with 35 and no digit appears more than once?
Q.19. In how many ways 5 girls and 3 boys be selected in a row so that no two boys are together.
Q.20. A committee of 7 has to be formed from 9 boys and 4 girls. In how many ways can this be done when the committee consists of at least 3 girls.
Q.21. Find the number of words with or without meaning which can be made using all the letters of the word AGAIN. If these words are written as in dictionary, what will be the 50th word?
Q.22. In how many ways can the letters of the word PERMUTATIONS be arranged if the
Paper By Mr. Anil Kumar Tondak