Is it true that if you know the radius of a circle you can double it to get the diameter?

Hurry if the population of of an ant hill doubles every 10 days and there are currently 100 ants living in the ant hill what will the ant population be in 20 days

Ron has 8 caps and 4 of his caps are blue. thes rest of his cap are red. how many of ron's caps are red

Sam is picking fruit from a basket that contains many different kinds of fruit. which set of events is independent?