Question

Jan.1 Jerome concocts a rumor and tells

Jan 1 Jerome starts a rumor and tells Beth. On Jan 2 they tell a new person. Jan 2 four people heard the rumor. On each subsequent day, each person who has heard the rumor spreads it to a new person. How many have heard the rumor by the end of Jan 8?

Answer 1

Number of people who have heard it
by the end of the day:

January 1 . . . . . 2
January 2 . . . . . 4
January 3 . . . . . 8
January 4 . . . . . 16
January 5 . . . . . 32
January 6 . . . . . 64
January 7 . . . . . 128
January 8 . . . . . 256
.
.
.
February 1 . . . . . 4,294,967,296
February 2 . . . . . 8,589,934,592 <=== more than the Earth's
human population.