Further Tree Diagrams (Edexcel A-Level Mathematics): Flashcards

It shows possible outcomes and their probabilities.

There are 18 discs in total: 5 red, 6 blue, 7 green.

$P(RR) = (5/18) \times (4/17) = 20/306 = 10/153$.

Sum probabilities of outcomes with at least one green.

Use $1 - P(\text{no green discs})$ for calculation.

$P(G|B) = 7/17$ after first disc selection.

Use $P(R,B)/P(B)$ conditional probability formula.

$P(RB) = \frac{5}{51}$ from previous outcomes.

$P(B) = 17/51$ from all outcomes with blue second.

$P(R|B) = P(R \text{ and } B) / P(B)$ for calculating.