And how long would it take to lose 20 pounds with this?
Ok, So the thing is I was wanting to just eat the Special K Cereal Bars, the reason for this is because I love them and it's just too hard to cook all healthy food, because I am the only one in a four member family actually going on a diet. So this is what I wanted to do:

Breakfast- Special K cereal bar
Lunch- Special K cereal bar
Dinner- Chicken breast with a serving of fruit and vegetables.
Ever since I started thats plenty for me to eat, I don't get very hungry..

Exercise-
30 minutes cardio- 4.5 mph on treadmill- 2 miles
Bunch of Sit ups, Push ups, and crunchs.
2 days a week- biggest loser weight loss yoga
lift 8 pound weights for about 10 minutes
hola hoop 10 minutes

I would like to lose 15-20 pounds
Starting weight: 135
Goal Weight: 115
Im 5'4

If I just stayed on the same diet and exercise routine for 3 months would I get to my goal weight?

(by the way even when I do lose my weight im still going to do cardio a few times a week and probably stay on the same diet cause I love it haha, yes i have tried this diet and exercise routine and i can handle it)