To solve this problem, we can use the concept of person-hours. If it takes 2 people to edit a 90-minute movie in 3 weeks, we can calculate the total person-hours required for this task.
Person-hours = Number of people * Time taken
For the first scenario:
Number of people = 2
Time taken = 3 weeks = 3 * 7 days = 21 days
Person-hours = 2 * 21 = 42 person-hours
Now, let's calculate the person-hours required for editing a movie with 10 people in 2 months.
Number of people = 10
Time taken = 2 months = 2 * 30 days = 60 days
Person-hours = 10 * 60 = 600 person-hours
Now, we can calculate the duration of the movie that can be edited in 600 person-hours.
Duration of movie = Person-hours / Number of people
Duration of movie = 600 / 10 = 60 minutes
Therefore, with 10 people working for 2 months, they would be able to edit a 60-minute movie.