The number of pumps in use at both a six-pump station and a four-pump station will be determined. give the possible values for each of the following random variables. (enter your answers in set notation.) (a) t = the total number of pumps in use t = incorrect: your answer is incorrect. (b) x = the difference between the numbers in use at stations 1 and 2 x = incorrect: your answer is incorrect. (c) u = the maximum number of pumps in use at either station u = incorrect: your answer is incorrect. (d) z = the number of stations having exactly two pumps in use z = incorrect: your answer is incorrect.