please i need help with all these questions

:. [412.5 Points] DETAILS wANEFMAcs 9.3.003. W N. Find the expected value E00, the variance Var(X) and the standard deviation [7(X) for the density function. [Round youl answers to four decimal places.) x) = i on [1, e] X E00 = :] Veda = [j = :1 600 l. [412.5 Points] DETAILS wANEFMAcs 0.3.034. W N. Find the median of the random variable with the probability density function given below. (Round your answer to four decir places.) x] = i on [1, e] I: X i. [412.5 Points] DETAILS WANEFMACG P.3.063. W N. Assuming that workers' salaries in your company are uniformly distributed between $15,000 and $?0,000 per year, calcula1 average salary in your company. 55:]