. Write the contrapositive of the following statement: “If a graph G has an Euler circuit, then G is not a tree.” 

2. Write the formal negation of the following statement: ∀ x ∈ D, x /∈ E. 3. 

There are 8 balls in a box: 3 red balls, numbered 1 through 3, and 5 green balls, numbered 1 through 5. If I reach into the bag and blindly pick up 4 balls, what is the probability of ending up with 4 green balls?