evinda
Gold Member
MHB
- 3,741
- 0
Hey! :)
An elevator of an apartment building with $4$ floors begins from the ground floor with $5$ people.Calculate the number of ways of getting off the elevator of $0$ zero people at the first floor , $2$ at the second floor, $2$ at the third floor and $1$ at the last floor.
I thought that it is:
$$\binom{5}{0} \cdot \binom{5}{2} \cdot \binom{3}{2} \cdot \binom{1}{1}=\frac{5!}{2! \cdot 3!} \cdot \frac{3!}{2!}=30$$
Could you tell me if it is right?
An elevator of an apartment building with $4$ floors begins from the ground floor with $5$ people.Calculate the number of ways of getting off the elevator of $0$ zero people at the first floor , $2$ at the second floor, $2$ at the third floor and $1$ at the last floor.
I thought that it is:
$$\binom{5}{0} \cdot \binom{5}{2} \cdot \binom{3}{2} \cdot \binom{1}{1}=\frac{5!}{2! \cdot 3!} \cdot \frac{3!}{2!}=30$$
Could you tell me if it is right?