Suppose we have an urn containing 100 balls. 20 are red, 10 are green, and the rest are neither red or green. What is the probability of grabbing at least one red ball, assuming the balls are not placed back in the urn? Assume two balls are always grabbed.
- Let A denote the event of getting at least one red ball.
- Let R1 denote the event of the first ball being red.
- Let R2 denote the event of the second ball being red.
Attempt at question:
P(A) = P(R1∩R2̅) + P(R1̅∩R2) + P(R1∩R2)
Is this the correct equation?