Probability Theory. In a given population of two-earner male-female couples, male earnings have a mean of $50,000 per year and a standard deviation of $15,000. Female earnings have a mean of $48,000 per year and a standard deviation of $13,000. The correlation between male and female earnings for a couple is 0.90. Let C denote the combined earnings for a randomly selected couple.

b. What is the covariance between male and female earnings?