In a certain country 54% of the population is male. It is known that 5% of the males are colour-blind and 2% of the females are colour-blind. A person is chosen at random and found to be colour-blind. By drawing a tree diagram, or otherwise, find the probability that this person is male.
Sajid is practising for a long jump competition. He counts any jump that is longer than 6 m as a success. On any day, the probability that he has a success with his first jump is 0.2. For any subsequent jump, the probability of a success is 0.3 if the previous jump was a success and 0.1 otherwise. Sajid makes three jumps.
(a) Draw a tree diagram to illustrate this information, showing all the probabilities.
(b) Find the probability that Sajid has exactly one success given that he has at least one success.
On another day, Sajid makes six jumps.
(c) Find the probability that only his first three jumps are successes or only his last three jumps are successes.
The people living in 3 houses are classified as children (C), parents (P) or grandparents (G). The numbers living in each house are shown in the table below.
| House number 1 | House number 2 | House number 3 | |
|---|---|---|---|
| 4C, 1P, 2G | 2C, 2P, 3G | 1C, 1G |
Rachel and Anna play each other at badminton. Each game results in either a win for Rachel or a win for Anna. The probability of Rachel winning the first game is 0.6. If Rachel wins a particular game, the probability of her winning the next game is 0.7, but if she loses, the probability of her winning the next game is 0.4. By using a tree diagram, or otherwise,
Hanna buys 12 hollow chocolate eggs that each contain a sweet. The eggs look identical but Hanna knows that 3 contain a red sweet, 4 contain an orange sweet and 5 contain a yellow sweet. Each of Hanna’s three children in turn randomly chooses and eats one of the eggs, keeping the sweet it contained.
(a) Find the probability that all 3 eggs chosen contain the same colour sweet.
(b) Find the probability that all 3 eggs chosen contain a yellow sweet, given that all three children have the same colour sweet.
(c) Find the probability that at least one of Hanna’s three children chooses an egg that contains an orange sweet.