Real-Life Math -- Solution
You first have to calculate the total number of frames in a 30-second animation. And you already know that 1 second has 24 frames.
Total frames = frames per second x total length
Total frames = 24 x 30
Total frames = 720
Now you simply divide that figure by 12 to figure out how many kicks the animator needs to design, since you want one every 12 frames.
720 / 12 = 60
So you have to tell the animator to design 60 kicks.
As for the physical length of the reel, you have to consider the ratio between how many frames you can fit on a foot of film, and how many frames you need to show 1 second of animation.
You need 24 frames to show 1 second. But you can only fit 16 frames on 1 foot of film. This means you need an extra half foot of film to show 24 frames.
So you need 1.5 feet of film to show 1 second of animation. Now you simply multiply that number by 30 to calculate the total length of the film.
Total length of reel = feet per second x total running time
Total length of reel = 1.5 feet x 30 seconds
Total length of reel = 45 feet
So you need 45 feet of film to show a 30-second piece of film.