JEE Main & Advanced
Mathematics
Permutations and Combinations
Question Bank
Definition of permutation, Number of permutations with or without repetition, Conditional permutations
question_answer
If \[{}^{n}{{P}_{4}}\ :\ {}^{n}{{P}_{5}}=1:2\], then \[n=\] [MP PET 1987; RPET 1996]