# Weekly service

In the class are 20 pupils. How many opportunities have the teacher if he wants choose two pupils randomly who will weeklies?

Correct result:

n =  190

#### Solution:

$n={C}_{2}\left(20\right)=\left(\genfrac{}{}{0px}{}{20}{2}\right)=\frac{20!}{2!\left(20-2\right)!}=\frac{20\cdot 19}{2\cdot 1}=190$ We would be pleased if you find an error in the word problem, spelling mistakes, or inaccuracies and send it to us. Thank you! Tips to related online calculators
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