One person had some money.
He gave one rupee to beggar and half of the remaining money was spent for buy something.
Same thing happened second day he gave one rupee to beggar from remaining money of first day.
This continued on till the sixth day when he had 0 rupee after giving 1 rupee to beggar,
Then how much money he had on first day?
He was left with 0 rupee on sixth day, this means he had only 1 rupee on sixth day.
so he had 1*2 + 1 = 3 on 5th day
on 4th day start 3*2 +1 = 7
on 3rd day start 7*2 + 1 = 15
on 2nd day start 15*2 + 1 = 31
on first day start 31*2 + 1 = 63