Area and cost of cladding



GCSE Marks:

GCSE Text:
As part of a DIY project, Jake wants to use wood cladding to cover a wall measuring 2.3m high and 2.9m wide.  Cladding comes in packs of 5 planks, with each plank measuring 129cm long and 19.4cm wide.  Each pack costs £13.50 plus VAT at 20%.

a)  How many packs will Jake need to buy to cover the wall area?

b)  What will be the total cost of the cladding for Jake’s wall?

A familiar style of GCSE question on area of rectangles.  Students need to decide to calculate the area of the wall and the area of a pack of planks (taking care to convert to a common unit before multiplying by 5).  It is important to stress to students that given the high marks awarded for a question of this type, even if the overall method proves too difficult for them, method marks will be awarded for working out any of the following:

  • Area of the wall
  • Area of one plank
  • Area of a pack of planks
  • Total price of one pack of planks

Discussions regarding rounding up or down to the nearest pack are also useful.

Extension Ideas:
Teachers could extend the learning by considering:

  • Asking students to work out wastage of material, given the rounding to the nearest full pack.
  • Introduce the idea of ‘online purchasing’ which has a delivery charge. Ask students to factor this into a new total. Delivery must also have VAT calculated on it.
  • Introduce a ‘10% off all ex-VAT prices’ offer for a bank holiday. Ask students to calculate how much could be saved if the cladding is bought at this lower price.
  • Introduce a ‘time to cut and apply one plank’ (maybe 10-15 mins), and ask students to give an estimate for the time to complete the job.

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