Do the area of the circle as a whole minus (72/360 x radius^2) and then minus the other grey area.
Answer:
Step-by-step explanation:
To find the probability of both of these occurring, you will multiply the probability of choosing a blue marble by the probability of choosing a purple marble (with no replacement after the first one).
Probability of choosing a blue marble: 17/120
Probability of choosing a purple marble: 18/119
17/120 x 18/119 = 3/140
You will have a 3/140 chance of both of these occurring.