Please tell me how long it takes for to lose 30 pounds?

3500 calories/1lb: You have to cut down 3500 calories in your diet to loose one pound if you cut down 500 calories per day, you will loose 1 pound in on week, and approx 4 lbs in a month your weight loss is based on extra calories you burn by exercising plus the calories you reduce in your diet so calculate for yourself, if you are negative 3500 cals per week, it will take 30 weeks.