level 1: 3
level 2: 3*3 = 3^2
level 3: 3^2*3 = 3^3
This is just a geometric progression, and you want the sum of the first four terms.
You ask your friends to help you spread the word about your upcoming picnic that you are
hosting at your house. You give an invitation to each of your three best friends. They in turn each give
invitations to three more friends. How many friends will have received an invitation after the fourth level of
friends has been invited?
1 answer
1 answer