Respuesta :
Answer:
C (20, 3) = 1140
Step-by-step explanation:
We are given that there is chorus of 20 singers and we are to find the number of different trios that can be selected from 20 singers.
This is a problem of combinations where the order of trios is not important.
[tex] C ( 2 0 , 3 ) = \frac { ( 2 0 ! ) } { ( ( 2 0 - 3 ) ! 3 ! ) } [/tex]
[tex]C ( 2 0 , 3 ) = \frac { 2 0 ! } { ( 1 7 ! ) ( 3 ! ) } [/tex]
[tex]C ( 2 0 , 3 ) = \frac{( 2 0 \times 1 9 \times 1 8 )}{( 3 \times 2 \times 1 )}[/tex]
C (20, 3) = 1140