Question

John saw full moon on a particular day. After how many days, he will be able to see the full moon again?

Answer 1

He will be able to see full moon approximately after 29 days because first, the moon size will decrease to zero, i.e. new mdcn day and then will increase from the 16th day, i.e. crescent moon will appear and finally on next 15th day, there will be a full moon again.