I need help with this question

A salesperson's monthly expenses ( in thousands of dollars) are exponentially distributed, with an average of 4.25 ( thousand dollars). A. Give the probability density function for the expenses. B. Find the probability that the expenses are more than $6,000. A. The probability density function is f(x) = D. . (Use integers or decimals for any numbers in the expression. Round to four decimal places as needed.) B. The probability that the expenses are more than $6,000 is D. (Round to four decimal places as needed.)