Question

Two events, X and Y, are independent of each other. P(Y) = 5/6 and P(X and Y) =1/3 . What is P(X) written as a decimal?

Answer 1

P(Y) = 5/6
Since they are independent, P(X & Y) = P(Y) * P(X)
Therefore:
1/3 = 5/6 * P(X)     Change 1/3 to 2/6, then multiply both sides by 6/5
2/6 * 6/5 = P(X)    
2/5 = P(X)
Written as a decimal, P(X) = .40