Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
6. Find
n
n
n
if
n
−
1
P
3
:
n
P
4
=
1
:
9
{ }^{n-1} \mathrm{P}_{3}:{ }^{n} \mathrm{P}_{4}=1: 9
n
−
1
P
3
:
n
P
4
=
1
:
9
.
Browse the problem library