Edexcel IGCSE Math B 10.I conditional probability
Practise conditional-probability questions by updating totals after each stage, completing the tree and multiplying or adding paths.
- Syllabus
- First assessment 2018
- Course
- Math B 4MB1
Practise conditional-probability questions by updating totals after each stage, completing the tree and multiplying or adding paths.
Table 1 gives information about the probability that a biased red six-sided dice will land on each of the numbers 1,2,5,7,9,11.

A biased blue six-sided dice has faces numbered 2, 4, 6, 8, 10, 12.
The probability that the blue dice lands on the number 2 is 0.24.
The probability that the blue dice lands on the number 4 is 0.12.
In a game Tai rolls the red dice once and the blue dice once.
The number that the red dice lands on is added to the number that the blue dice lands on to give his score in the game.
Given that his score is less than 6, find the probability that the red dice lands on the number 2.
Probability that the score is less than 6:
0.1×0.24+0.15×0.24+0.1×0.12=0.072
Required conditional probability:
0.0720.15×0.24=0.5
Final answer:
0.5