Skip to content
MathsGenie logo
Quick links
Open app

Course home

  1. A Level
  3. Maths OCR
  5. Question bank

2.3.2 Diagrams to assist probability calculations

Medium
1234567891011121314151617181920212223242526272829
Question 1

Two jars, J1 J_1\,J1​ and J2J_2J2​, contain blue, white, and black marbles. Jar J1 J_1\,J1​ contains 4 blue marbles, 3 white marbles, and 3 black marbles. Jar J2 J_2\,J2​ contains 2 blue marbles, 5 white marbles, and 1 black marble. Sam picks one marble at random from jar J1 J_1\,J1​ and places it into jar J2J_2J2​. Sam then picks one marble at random from jar J2J_2J2​.

a.

Draw a tree diagram to represent this information.

[2]
b.

Find the probability that Sam picks two marbles of the same colour.

[2]
c.

Given that both marbles are the same colour, find the probability they are both black.

[2]

2.3.2 Diagrams to assist probability calculations Questions

  1. A Level
  2. /Maths
  3. /2.3.2 Diagrams to assist probability calculations