Can someone please help with this problem and explain -Thank you!!

In a recent survey, 15% of families in the US have no children living at home.Twenty four percent have one child living at home. Thirty one percent have two children living at home. Eighteen percent have three children living at home. Twelve percent have more than three children living at home.

1. If a family is selected at random, what is the probability the family will have three or more children living at home?

1. If 20 families are selected at random, what is the probability the families will have one to three children living at home?