Given:
Number of people bought tickets for comedy =

Number of people bought tickets for horror =

Number of people bought tickets for kids movie =

To find the number of people who bought tickets for the action movie.
Let us take,
Total number of tickets = 1
Now,
Total number of tickets for comedy, horror and kids movie are =

So,

LCM of 5,4,10 = 20
=

=

Rest are action movie's tickets.
Therefore,
Number of action movie tickets =

=

=

Hence,
The number of people who bought the tickets for action movie is
.