Christmas roast

Christmas roast

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about an equation for cooking a roast.

illustration: roast beef

Maaka is cooking Christmas roast. The recipe book says "Cook for 40 minutes for each kilogram of meat plus an extra 20 minutes".
 
  t is the total cooking time (in minutes)
w is the weight of the roast (in kilograms).
 
a)
Complete this formula to show how the cooking time varies according to the weight of the meat.
 
T = ___________________
 
b) How many minutes will it take to cook a roast that weighs
 
 
i)
 
ii)
3kg?   __________ minutes
 
1.5 kg?   __________ minutes
 
c) If a roast took 200 minutes to cook, what would it weigh?   __________ kg
Task administration: 
This task is completed with pencil and paper only.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Equations and expressions
Keywords: 
linear equations, substitution
Description of task: 
Students write and solve linear equations to describe cooking times.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Using symbols and expressions to think mathematically, sets 6-7
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

   

Y10 (10/2000)

a)

   

40w + 20

moderate

b)

i)
ii)

140 [Accept 2h 20 min]
80 [Accept 1h 20 min]

easy
easy

c)

   

4.5

easy