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. (I've asked this question before but the answer I got was 384 and it was incorrect)

Answer 1

64

Explanation:

In this problem n is 6 which represents the sixth and final hour of the period. Therefore gn = g6.

g1 = 2 which is the first value in the sequence which corresponds to the first hour where 2 people know the rumor.

r = the common ratio is 2, because each successive hour the people who know the rumor doubles... {2, 4, 8...}.

Substitute into equation: g6 = 2 x 26-1 = 2 x 25 = 2 x 32 = 64 Answer is 64.