Let XXX and YYY be two random variables such that Var(X)=4,Var(Y)=9Var(X)=4, Var(Y)=9Var(X)=4,Var(Y)=9, and ρ(X,Y)=−0.5\rho(X, Y) = -0.5ρ(X,Y)=−0.5. What is Var(X+Y)Var(X+Y)Var(X+Y)?
4
7
10
13