How much workout is needed to be like them?

I'm a student at university and quite busy. I have classes in the morning and the noon and have to work in the evening. I do not have no energy to work out at night. So I have to work out in the morning. I work out like 15 mins in the morning and more than 30 mins for the weekends.
Is it not enough? Well I'm quite skinny and don't have so much fat on my abs.
How much workout is needed to be like them?
How much workout is needed to be like them?
How much workout is needed to be like them?
Post Opinion