A bag contains 5 red, 3 blue and 2 green marbles of identical size and weight. One marble is drawn at random from the bag. Define the following events:
Event R: drawing a red marble;
Event G: drawing a green marble.
a. (i) Calculate P(R) and P(G).
b. (ii) Identify which event, R or G, is more likely. Show your working.
c. (iii) By how much does the probability of the more likely event exceed that of the other event? Express your answer as a simplified fraction.