Question

nP3 : (n+1)P3= 3 : 4

Answer 1

Given, nP3 : (n+1)P3 = 3 : 4

=> nP3/(n+1)P3 = 3/4

=> (n+1)P3/nP3 = 4/3

=> [(n+1).n.(n-1)]/[n.(n-1).(n-2)] = 4/3

=> (n+1)/(n-2) = 4/3

=> 3.(n+1) = 4.(n-2)

=> 3n + 3 = 4n - 8

=> 3 + 8 = 4n - 3n

=> 11 = n

Therefore, n = 11

if this helps you, please marks this as brainliest

Answer 2

Hy friend!
nP3/(n+1)P3=3/4
n!/(n-3)!/(n+1)!/(n+1-3)!=3/4
n!(n-2)!/(n-3)!(n+1)!=3/4
n!(n-2)(n-3)!/(n-3)!(n+1)n!=3/4
now (n-3)!(n)! Cancel
n-2/n+1=3/4
3n+3=4n-8
n=11 ans
Hope it helps u!