What is 13% of 400?
A.52
B. 413
C.520
D.5200​

Well if you pick a machine to work on and that's gonna be your exercise if you don't stick to that machine your muscle strength your muscle mass rather will change because you haven't been doing it you change something in your exercise routine which changes your body's form of dealing with things for example you might become weaker or stronger depending on what kind of exercises you do in whether or not the machine you picked actually your muscles grow.

This is first hand knowledge, top-level athletes, successful business people and achievers in all fields all  set goals. setting  goals  gives you long-term vision and short-term motivation . it focuses your acquisition of knowledge, and you to organize your time and your resources so that you can make the very most of your life.