Please help me with the question, and show the work and explanation. thank you

E. In a recent election campaign. one of the major political parties recently announced a policy to charge commercial users for the water they use. Two different tariffs are proposed: one for high water users {eg. dairy farmers] and one lower water users {eg companies bottling water]. Suppose thattbe tariffswill comprise ofadailyxed cost and aperunit charge andcanbe represented as followsE: Calf. w} = f+l12w can. to] = o.3r+o.5 w ones\";2 where t represents time [measured in days} and w represents water usage in cubic metres. for w 5 SD. A particular farmer is tryingto decide which tariff to use. The weekly [i.e. T days] water usage for this farmer can be modelled byan exponential random variable W, with density f{ w} = Die\"'2'". Total for Question 5: 13 moth [a] Find the expected value and variance for W. [3 mrb [b] Find the expected value and variance of the weekly cost ofwater under tariff A. [3 math} [c] Find the expected value of the weekly cost of water under tariff B. [3 With?) [d] Which tariffwould you reconunend that the farmer? Justifyyour answer. Refer to your answers [4 With?) above and other relevant analysis. For full marks you must conduct some analysis beyond that which you have already undertaken in parts {chj. [e] Find the variance of the weekly cost ofwater under tariff B. [4 [bonus]}