Central Limit Theorem Question

[Kalinka35]

Homework Statement

On average one third of seniors at a college will be bring parents to the graduation, one third will bring one parent and the remaining third will not bring any parents. Suppose there are 600 seniors graduating this year. Estimate the probability that more than 650 parents will attend the graduation.

Homework Equations

The Central Limit Theorem

The Attempt at a Solution

I let X = the number of parents in attendance and X_i = the number of parents brought by student i. So X = X₁+...+X₆₀₀.
I found that E(X)=600 and in order to use the Central Limit Theorem I need to know the variance of X, but this is what is tripping me up.
Var(X) = E(X²) - (E(X))² but I don't know how to find (E(X))². Is there an entirely different approach that I'm missing?

 

[Kalinka35]

Okay, never mind I think I got it...