Consider a small ferry that can accommodate cars and buses. The toll for cars is $3, and the toll for buses is $10. Let X and Y denote the number of cars and buses, respectively, carried on a single trip. The joint pmf of X and Y is given in the table below. P(x, y ) 0 2 O 0.060 0.090 0. 150 0.020 0.030 0.050 2 0.020 0.030 0.050 3 0.010 0.015 0.025 0.040 0.060 0. 100 UI A 0.050 0.075 0.125 It is readily verified that X and Y are independent. (a) Compute the expected value, variance, and standard deviation of the total number of vehicles on a single trip. (Round your standard deviation to two decimal places.) expected value vehicles variance standard deviation vehicles (b) If each car is charged $3 and each bus $10, compute the expected value (in $), variance, and standard deviation (in $) of the revenue resulting from a single trip. (Round your standard deviation two decimal places. expected value $ variance standard deviation $