These are 'What if' situations. I would succeed in the examinations if I work hard. Would I be able to spend a healthy life depends on my eating and activity habits. These are situations in which our actions, and other's responses, further unfold a number of possibilities, which were previously hidden. In every situation, man is accountable for moral choices that the situations offer.
Man is thus partly free and partly subject to deterministic forces.
This however does not affect his accountability in the hereafter. He would be held accountable only for acts that he intended to do out of his free will. Of virtues he could not perform due to his limitations, he would not be asked. Man is therefore free to win heaven or hell. He can make his own destiny.