N-Ach (need for achievement) refers to an individual's desire for accomplishment, learning or mastering of skills or control. In this case, Jill is in need for achivement. Therefore, she works hard. If it's not enough, she will train for a marathon. If that couldn't fulfill her need, she would surely find something else. This need for achievement, or achievement needs, can present in any way that feels like a challenge or a goal for the individual: could be a marathon as it could be working more as it could be learning something new, etc.
