Ответ:

1) Jack can discuss this problem with his brother. If Jack explains it properly, brother certainly will do something not to disturb him.

2) Sarah can talk to her parents about this problem, they will certainly understand it and at least have visitors not so often.

3) Freya can talk to her parents about this problem. But if they won't give her a new bike, she can get a job to get money for the bike herself.