(a)[2]
Complete the tree diagram by inserting the missing probabilities.
(b(i))[2]
Calculate the probability that both pencils drawn are red.
(b(ii))[3]
Calculate the probability that at least one of the pencils is red.
Mathematics 0580 · IGCSE · Probability of combined events
Probability of combined events — practice question
A box holds 6 red pencils together with 8 blue pencils. One pencil is selected at random and is not put back. Then a second pencil is selected at random. In the tree diagram, several probabilities have been left blank. The probabilities already shown are $\frac{6}{14}$ for choosing red first and $\frac{8}{13}$ for choosing blue second given that red was chosen first.