Answer: [tex]5+5^2+5^3+5^4[/tex]
Explanation:
1) First forwarding: 5 e-mails
2) Second forwarding: 5 * 5 = [tex] 5^{2} [/tex]
3) Third forwarding: 5 * 5 * 5 = [tex] 5^{3} [/tex]
4) Fourth forwarding: 5 * 5 * 5 * 5 = [tex] 5^{4} [/tex]
The number of people who have received the email, after Kris started forwarding the e-mail, not counting Kris, is:
[tex]5+5^2+5^3+5^4[/tex]
