This question was reported to be attempted by majority of the candidates and they performed well in it. However, in part (a), it was also reported that a good number of the candidates could not manipulate the negative powers involved. Some candidates wrote 2-1 as 2 – 1 and this affected their final answer.
Candidates were expected to subtract from 1 to have 1 - = =
Thereafter, they would find -½ = ½ = . The fraction has to be inverted because of the negative power. This fact eluded some candidates.
6- ½ = 6 = 8. Similarly, 2-1 = 1 = . Therefore, 6- ½ x 2-1 = 8 x ½ = = 4.

In part (b), candidates were able to show that if is the exterior angle, then the interior angle = 108 + . Now, interior angle + exterior angle = 180o i.e. + 108 + = 180o. Solving this equation gave = 36. The number of sides was obtained by dividing 360o by the value of the exterior angle which gave = 10 sides.