M L Aggarwal Solutions for Chapter: Permutations and Combinations, Exercise 1: EXERCISE 8.1

Find the value of $\frac{\left(n+2\right)!}{\left(n+1\right)!}$.

Evaluate $\frac{n!}{\left(n-r\right)!}$ when $n=12,r=3$.

Convert into factorials: $3\times 6\times 9\times 12\times 15\times 18$.

Find the value of $n,$ if $\left(n+1\right)!=20\left(n-1\right)!$.

Find the value of $n,$ if $\frac{1}{5!}+\frac{1}{6!}=\frac{n}{6!}$.

Find the value of $n,$ if $\frac{1}{6!}+\frac{1}{7!}=\frac{n}{8!}$.

Find the value of $n,$ if $\frac{n!}{\left(n-2\right)!}=110$.

Find the value of $n,$ if $\frac{n!}{2\left(n-2\right)!}$ and $\frac{n!}{4\left(n-4\right)!}$ are in the ratio $1:6$.