If I eat only Breakfast, Lunch and Dinner and drink lots of water and do 3 30min of exercise will I lose more weight?

Depends what you are doing now... If you're doing more exercise and eating more healthily than you were before, you should lose weight, until you hit your natural weight on that diet.

I am doing only 1 exercise a day
Will doing 3 be better to lose more weight

Of course, the more work you do, the more calories you must expend in order to do it.

I'm sure someone can give a more detailed answer than I can :)

If I eat only Breakfast, Lunch and Dinner and drink lots of water and do 3 30min of exercise will I lose more weight?

You really didn't give more info, like what are you eating for breakfast, lunch and dinner. The water part is great. In order to keep weight off or to lose, you need to restructure your eating habits, if there bad. Nothing fried, nothing fatty, no fast foods, none of your favorite foods, (you know why). No unhealthy snacks, salty, sugary, or greasy, no cakes, cookies unless there low fat, low sugar. No seconds after you eat. Do you drink sweet drinks, like colas they need to be cut out. Are you exercising, this is a big part of weight lossThe key to maxium fat loss is to work out 30-60 minute sessions 3-4 x per week, Fat loss is 50% exercise and 50% nutrition. So if you give a little more info:cool: , like how much you want to lose, and what are your weight loss goals, I could help a lot more.