The solution id (0, 2). This is because it is where the two lines meet.
You can find percentages like this by taking the total number of questions dividing it by 100 to find out how much each question was worth, then multiplying by the number correct.
So, 85 ÷ 100 ≈ 1.18
1.18 x 68 ≈ 80
So, the score was 80%.
