Complementary probabilities

Complementary probabilities

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about probability as a fraction.
 
a)

 

 The prizes in a raffle are either a supermarket voucher or a petrol voucher. The probability of getting a supermarket voucher is \(3 \over 5\).

What is the probability of getting a petrol voucher?   __________
b) The pens in a pencil case are either blue, green, or red. The probability of getting:

  • a blue pen is \(4 \over 7\)
  • a green pen is \(1 \over 7\)

What is the probability of getting a red pen?   __________
c) The balloons given out at a birthday party are either purple, pink, orange, or yellow. The probability of being given:

  • a purple balloon is \(5 \over 11\)
  • a pink balloon is \(1 \over 11\)
  • an orange balloon is \(2 \over 11\)

What is the probability of being given a yellow balloon?   __________

  
Task administration: 
This task is completed with pencil and paper only.
Level:
4
Curriculum info: 
Maths, Statistics, Probability
Keywords: 
probability, fractions
Description of task: 
Students use fractions to describe the probability of receiving cellphones of certain colours as a prize.
Curriculum Links: 
This resource can be used to help to identify students' understanding of computing and writing likelihoods as fractions, decimals or percentages.
 
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Interpreting statistical and chance situations, sets 4-5
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
   

Y8 (03/2001)
a) 2/5 (Accept .4) very easy
b) 2/7 (Accept .286) very easy
c) 3/11 (Accept .273) very easy