I need help on this algebra problem and the faster the better.

Question

Chain emails are emails with a message suggesting you will have good luck if you forward the email on to others. Suppose a student started a chain email by sending the message to 3 friends and asking those friends to each send the same email to 3 more friends exactly 1 day after receiving it.

a. Write an explicit formula for the sequence that models the number of people who receive the email on the 𝑛th day. (Let the first day be the day the original email was sent.) Assume everyone who receives the email follows the directions.

b. When will the number of people receiving the e-mail exceed 100? Make a table to show your work.

Answer 1

a_n = 3(3)^n-1

100 < 3ⁿ

3⁴ < 100 < 3ⁿ < 3⁵