SOLUTION(S) Know a pair of spur gears
Pinion Diameter = 7.5 in
For Pinion Diameter (dp) = 15 in, Gear Diameter (dg) = 4 dp
Hence, dp = 3 in, dg = 12 in
For Pinion Diameter (dp) = 8 in, Gear Diameter (dg) = 24 in
Hence, dp = 3 in, dg = 12 in
For Pinion Diameter (dp) = 8 in, Gear Diameter (dg) = 96 in
Hence, dp = 3 in, dg = 12 in
For the module were a higher, the pitch diameter of the gear and the remaining teeth would be more on both the pinion and gear for the same number of teeth.