How many teeth must F have if all gears have the same diametral pitch?

1. An annular gear A on shaft S1, has 120 teeth and drives a pinion B having 15 teeth, keyed to shaft S2. Compounded with B is a 75-tooth gear C which drives a 20-tooth gear D on shaft S3. Compounded with gear D is gear E having 144 teeth driving gear F on shaft S4. The axis of S4 is collinear with the axis of S1. All shafts are parallel and in the same plane.

(a) How many teeth must F have if all gears have the same diametral pitch?

(b) If S1 is the driving shaft, determine the train ratio.

(c) If the gears have a diametral pitch of 4, what is the distance between shafts S1 and S3?