You can collect 6 wedges altogether per one session. You need to earn more points for each wedge unlocked.
For the 5-Round:*** Spoiler - click to reveal ***1st wedge: 2,000 points
2nd wedge: 6,000 points
3rd wedge: 12,000 points
4th wedge: 20,000 points
5th wedge: whoever correctly answers the final round answers.
6th wedge: whoever correctly answers the final round answers.
However, you need to earn less points for the 3-Round so it may be faster to get wedges.
For the 3-Round:*** Spoiler - click to reveal ***1: 700 points
2: 2,000 points
3: 4,000 points
4: 8,000 points
5: whoever correctly answers the final round answers.
6: whoever correctly answers the final round answers.
If you get all 6 wedges in each session, you will only need to play 5 sessions. Hope that helps. Any updates or comments, let me know. Have fun!
