Permutation and Combination: Formulae

What is the arrangement of 'r'-things out of 'n' called?

• Permutation

• Combination

• Preposition

• Combinization

What is the selection of 'r'-things out of 'n' called?

• Permutation

• Combination

• Preposition

• Combinization

In which of these terms ORDER matters?

• Permutation

• Combination

• Precalculation

• Combinization

In which of these terms ORDER does NOT matter?

• Permutation

• Combination

• Precalculation

• Combinization

Select a leadership team of 3 out of 10

• None of them

• $\frac{10!}{3!}$

• $\frac{10!}{7!}$

• $\frac{10!}{3!7!}$

Select a leadership team of 3 out of 10. One of them must be VP, one - Manager and the last one - Product Developer.

• None of them

• $\frac{10!}{3!}$

• $\frac{10!}{7!}$

• $\frac{10!}{3!7!}$

What is the formula of Permutation?

• $P_r^n=\frac{n!}{\left(n-r\right)!}$

• $P_r^n=\frac{n!}{\left(n+r\right)!}$

• $P_r^n=\frac{n!}{r!}$

• $P_r^n=\frac{n!}{r!\left(n-r\right)!}$

What is the formula of Combination?

•  $C\ _r^n=\frac{n!}{\left(n-r\right)!}$ 

•  $C\ _r^n=\frac{n!}{\left(n+r\right)!}$ 

•  $C\ _r^n=\frac{n!}{r!}$ 

•  $C\ _r^n=\frac{n!}{r!\left(n-r\right)!}$ 

Select 2 out of 5 who get Ice-Cream.

• $\frac{5!}{3!}$

• $\frac{5!}{2!3!}$

• $\frac{5!}{2!}$

• 1

Select 2 out of 5 who get Ice-Cream. One of them gets Vanilla & the other gets Chocolate

• $\frac{5!}{3!}$

• $\frac{5!}{2!3!}$

• $\frac{5!}{2!}$

• 1