The circular archery target shown, on which 1, 2, 3 or 5 points can be scored, is divided into four parts of unequal area by concentric circles. The radii of the circles are 3cm, 9cm,15cm and 30cm. You may assume that a randomly fired arrow pierces just one of the four areas and is equally likely to pierce any part of the target.

a. Show that the probability of scoring 5 points is 0.01.

b. Find the probability of scoring 3 points, 2 points and 1 point with an arrow.

c. Given that an arrow does not score 5 points, find the probability that it scores 1 point.

d. Given that a total score of 6 points is obtained with two randomly fired arrows, find the probability that neither arrow scores 1 point.