2010007105

SubArea: 
Combinatorics
Level: 
A
Project ID: 
2010007105
Source Problem: 
9000148909
Accepted: 
0
Clonable: 
1
Easy: 
0
There are \(20\) girls and \(10\) boys in the class. How many ways are there to designate a president and vice-president of the class if it is required that at least one position will be held by a girl.
\(2\cdot 20\cdot 10 + 20 \cdot 19 =780\)
\(2\cdot 20\cdot 10=400\)
\(20\cdot 19 =380\)
\(20\cdot 10 =200\)