Question

Each hour, every person who knows a rumor tells two other people. If one person starts the rumor, then after the first hour, three people know the rumor. The next hour, those three people each tell two more people. After eight hours, how many people will know the rumor? You do not have to include units in your answer.

Answer 1

384

Explanation:

if each person who knows it tell 2 people then its doubling every hour

and for 8 hours the equation is

3x
`2^(7)` (to seventh power because 1st hour already happened)

3x2x2x2x2x2x2x2

6x2x2x2x2x2x2

12x2x2x2x2x2

24x2x2x2x2

48x2x2x2

96x2x2

192x2

384