Here is another variation.
A fresh lake gets infested with algae and the amount of algae doubles every day. The algae covers the whole lake in 10 days. How many days did it take the algae to cover half the lake?
A fresh lake gets infested with algae and the amount of algae doubles every day. The algae covers the whole lake in 10 days. How many days did it take the algae to cover half the lake?