The joint density function for a pair of random variables X and Y is given. (Round your answers to four decimal places.) f(x, y) = Cx(1 + y) if 0 ≤ x ≤ 2, 0 ≤ y ≤ 6 0 otherwise (a) Find the value of the constant C. (b) Find P(X ≤ 1, Y ≤ 1). (c) Find P(X + Y ≤ 1).

Which of the following statements is true? a. the irrational number system is not closed under multiplication, because the product of two irrational numbers is always a rational number. b. the irrational number system is not closed under multiplication, because the product of two irrational numbers is not always an irrational number. c. the irrational number system is closed under multiplication, because the product of two irrational numbers is always an irrational number. d. the irrational number system is closed under multiplication, because the product of two irrational numbers is always a rational numbers. reset submit