An easier way than to go for the bonus games is for both players to earn the wedge at the same time
Pick 2 players (number of controllers not important).
Choose a subject for player 1 (player 2 bets they will get it correct) Answer correctly (P1 - 2 points, P2 - 1 point)
Player twos turn - choose the same subject (player 1 bets that they will get it correct) Answer correctly (P1 - 3 points, P2 - 3 points)
Player ones turn, choose the same subject again (bet on correct) Answer correct. Both players now have enough for the wedge so it goes straight into a wedge off.
As described in the other solution, answer correctly for the player who wants the cheevo, incorrectly for the other player)
Using this method the whole cheevo can be done in as little as 5 questions from the start of the game (3 to get the wedges, 2(one each) for the wedge-off)
Tip: Stay along the spokes as it gives you a better chance of getting matching subjects. There is one of each subject 1 square away from the centre, one of each 2 squares away and so on so ALMOST any roll of the dice will lead to a choice of a matching subject