Question

A particular lake has water lilies growing on it. On the first day, there is one water lily. Each day, the number of water lilies doubles. After 30 days, the whole lake is full of lilies. On which day did the water lilies cover only half of the lake?

Answer 1

day 29

Explanation:

on day 29, it is half full, on day 30, it's full, on day 28, it is quarter full.