To lose weight and keep it off: You will need a high amount of physical activity unless you also adjust your diet and reduce the amount of calories you're eating and drinking. Getting to and staying at a healthy weight requires both regular physical activity and a healthy eating plan. The CDC has some great tools and information about nutrition, physical activity and weight loss. For more information, visit Healthy Weight. Reduce Your Risk of Cardiovascular Disease
If 10 revolutions per minute equal 1 mile per hour, then 1 rpm = 0.1mph. At 25rpm you should br producing 2.5mph, and at 35rpm you should get 3.5mph. I would suggest you measure the length or distance you are actually achieving, and see if this stacks up.
The way Iâve always seen it is that a human on a bicycle has an effective rpm range of between 60 and 150 rpm where they can produce power. Compared to a motor vehicle which typically produces power from 1,000 to 6,000 rpm you can start to see the % difference in cadence (rpm) within the same gear.