Question

A lily pad is growing on a lake and it grows 2 times bigger a day. On the 20th day it was covering the whole lake. On what day was it covering one eight of the lake?

Answer 1

On the 19th day it covered 1/2 of the lake.
On the 18th day it covered 1/4 of the lake.
On the 17th day it covered 1/8 of the lake.