The Johnsons are having a family reunion and they want to order T-shirts. 36 people will be attending the reunion. There will be twice as many children as adults at the reunion. Set up a
system of equations that represents the numbers of adults and children that are attending the
reunion and solve the system to figure out how many adult and child T-shirts they need to buy.
(hint: let a=the number of adults, and c=the number of children)