Timing of ‘Sehar and Iftaar’?

  How old should be a person to start Waajib Fast (Roza)?

 Giving fitra in joint faimly system

   If one does not know the correct number of ‘Qaza’ Fast (Rozay), then

 how many fast will it keep?

  Is it compulsory for children to complete ‘Qaza’ fast ( Rozay) of dead parents?

 Can Kaffarah of Sixty people be given to one to two persons