At a benefit concert, nine bands have volunteered to perform but there is only enough time for seven of the bands to play. How m

Question

bija089 [108]

2 years ago

9

At a benefit concert, nine bands have volunteered to perform but there is only enough time for seven of the bands to play. How m

any lineups are lineups (Simplify your answer. Type an integer or a fraction.)

Mathematics

1 answer:

Harrizon [31] · Answer 1 · 2022-03-23T17:05:01+03:00

Answer: Hi, so here you have 9 bands and time fo only 7, then if the order matters, for the first band you have 9 options, for the second you have 8 options (because one of them already played), for the third band you have 7 options, and so on.

the total number of combinations is 9*8*7*6*5*4*3 = 181440 combinations

If the order of the band doesn't matter, then you need to do the combinatory between 9 and 7 is:

$\frac{9!}{(9-7)!*7!} = 9*8/(*2)$ = 36 combinations, that is the same of dividing 181440 by 7!.