Before we begin to solve this, we should have a couple of things in mind. We should know how to convert hours to minutes, and how to find unit rate.
To convert minutes to hours, we simply multiply it by 60. Let's go ahead and convert 2.5 hours to minutes.
2.5*60=150
Now we know that there are 150 minutes in 2.5 hours. Keep that in mind because we will need it later.
Now we will begin with unit rate. Unit rate, in this case, is how many minutes it takes to download a 1 minute clip. To find this, we should divide 10 by 40, because it takes 10 minutes to do a 40 minute show. This gives us .25. Now, we should multiply that .25 by 150 to represent 150 minutes. this yields a result of 37.5.
Using the logic above, we know it would take 37.5 minutes to download a 2.5 hour movie.