*I'll give you £1 for your first birthday. Then, the amounts that I give you each year will double every time*

and Grandma said :

*I will start by giving you £1 for your first birthday. Then, the amount I give you will be the combined total of all the last birthday presents that I have ever given you up to that point. Plus, every birthday you have that's a multiple of five, I'll give you an extra five pounds.*

a)What amount of money do they each pay you for your 15th birthday

and

Who would have given you the most after 27 years?