Tobias sent a chain letter to his friends, asking them to forward the letter to more friends. The number of people who receive the email increases by a factor of

4

44 every

9.1

9.19, point, 1 weeks, and can be modeled by a function,

P

PP, which depends on the amount of time,

t

tt (in weeks).

Tobias initially sent the chain letter to

37

3737 friends.