Simon, Marc and Wilson sat for their Math exam. The average score of Simon and Marc was 85 marks. The average score of Marc and Wilson was 91 marks. The average score of Simon and Wilson was 82 marks.

1. Find the total score for each pair of boys

Total of Simon and Marc = $85 \times 2 = 170$
Total of Marc and Wilson = $91 \times 2 = 182$
Total of Simon and Wilson = $82 \times 2 = 164$

2. Find the total score of all three boys

Sum of the three totals = $170 + 182 + 164 = 516$
Since each boy is counted twice in this sum, the total score of the 3 boys is $516 \div 2 = 258$

3. Calculate the average score of the three boys

Average = $258 \div 3 = 86$

1. Calculate the increase in the average score

Increase in average = $\frac{7.5}{3} = 2.5$

2. Calculate the new average score

New average = $86 + 2.5 = 88.5$