Permutation and CombinationHard
Question
The number of permutations which can be formed out of the letters of the word ″SERIES″ taking three letters together, is:
Options
A.120
B.60
C.42
D.none
Solution
SERIES
S - 2, E - 2 , R, I
case-I when all letter distinct is
4C3 × 13 = 4 × 6 = 24
case-II when 2 letters are same the
2C1 . 3C1 ×
= 2 . 3 . 3 = 18
total number is 24 + 18 = 42
S - 2, E - 2 , R, I
case-I when all letter distinct is
4C3 × 13 = 4 × 6 = 24
case-II when 2 letters are same the
2C1 . 3C1 ×
= 2 . 3 . 3 = 18total number is 24 + 18 = 42
Create a free account to view solution
View Solution FreeMore Permutation and Combination Questions
Consider all permutations of digits 1,2,3.....9 such that sum of digits between -(i) 1 and 2 (including 1 and 2) is 12 (...There are 12 points in a plane of which 5 are collinear. The number of distinct quadrilaterals which can be formed with ...The number of words which can be formed from the letters of the word ′SCHOLAR′ which begin with A and end wi...The number of rectangles in the adjoining figure is -...Let $S = \{ 1,2,3,4,5,6,7,8,9\}$. Let x be the number of 9-digit numbers formed using the digits of the set S such that ...