JEE Main202310 Apr 2023Morning ShiftMathematicsPermutation and CombinationActual
The number of permutations, of the digits 1 , 2 , 3 , … , 7 without repetition, which neither contain the string 153 nor the string 2467 , is _______ .
Correct answer
0
Step-by-step solution
Given, The number 1 , 2 , 3 , . . . . , 7 Now total numbers of 7 digit number will be 7 ! without repetition, Now total numbers which contain string 154 will be 5 ! Total numbers which contain string 2367 will be 4 ! And number which contain both string 2367   &   154 will be 2 So, total number which does not contain string 154 or 2367 will be 7 ! - 5 ! + 4 ! - 2 = 5040 - 120 + 24 - 2 = 5040 - 142 = 4898 Hence this is the required answer.