Solution:
The following information about the chain email can be Written as follows:
1 Person Email →→6 Persons (E-mail) →6² Persons (E-mail)→6³ Persons (E-mail)+.........few Days
As you can see the number of email sent starting from person 1 to 6 persons to 36 persons to 216 persons, forms a Geometric pattern.
So, Sum of the Series = 1 + 6 + 36 + 216 + 1296 +......+ for n days
=
Formula for n terms of a geometric series
For, Common ratio (r)≥1
Sum of above geometric series up to n terms