To calculate the expected value of playing this game, we need to multiply the value of each possible outcome by its probability of occurring and then add these values together. In this case, there is 1 gold marble, 6 silver marbles, and 28 black marbles in the bag, for a total of 35 marbles. So, the probability of selecting a gold marble is 1/35, the probability of selecting a silver marble is 6/35, and the probability of selecting a black marble is 28/35. The value of winning $3 if a gold marble is selected is $3 * (1/35) = $0.09. The value of winning $2 if a silver marble is selected is $2 * (6/35) = $0.34. And the value of losing $1 if a black marble is selected is -$1 * (28/35) = -$0.80. Adding these values together, we get $0.09 + $0.34 - $0.80 = -$0.37. Therefore, the expected value of playing this game is approximately -$0.37.