Matt, Noah, Olivia and Penny are at the Christmas market.
A Christmas tree seller is selling decorated and undecorated trees.
There is one more decorated tree than undecorated tree.
Matt says that the number of decorated trees is prime.
Noah says the total amount of trees is more than 8 and less than 12.
Olivia says that there are 4 undecorated trees.
Penny says that Olivia or Noah are lying.
Only one of the four are lying.
How many trees are there?
Solution is here.