A,B,C,D has 45,27,78,20 teeth respectively and the gears A and B are connected in the same shaft gear C has 100rpm, Calculate the rpm of gear D

Sure, here's how you can calculate the RPM of gear D:

Step 1: First, we need to find the RPM of gear B since it is connected to gear A. The formula to calculate RPM is (RPM of driving gear * Number of teeth on driving gear) / Number of teeth on driven gear.

So, RPM of gear B = (RPM of gear A * Number of teeth on gear A) / Number of teeth on gear B = (100 RPM * 45 teeth) / 27 teeth = 166.67 RPM

Step 2: Now, we need to find the RPM of gear D. Since gear B and C are connected, we use the same formula.

So, RPM of gear D = (RPM of gear B * Number of teeth on gear B) / Number of teeth on gear D = (166.67 RPM * 78 teeth) / 20 teeth = 625 RPM

Therefore, the RPM of gear D is 625.