4400 Higher November 2005 Paper 3 Q8

EdexcelHigherOld spec5 marksForming Equations

8 This rule can be used to work out the number of litres of paint needed to cover the walls of a room, using the length, width and height, in metres, of the room.

Flow chart: Add the length and the width, then Multiply your result by the height, then Then divide by 6, giving Number of litres needed

A room has length \(L\) metres, width \(W\) metres and height \(H\) metres.
\(N\) litres of paint are needed to cover the walls of the room.

(a) Find a formula for \(N\) in terms of \(L\), \(W\) and \(H\). (3)

The perimeter of the room is \(P\) metres.

(b) Find a formula for \(N\) in terms of \(P\) and \(H\). (2)

Mark scheme (a)

Scheme	Marks
\(N = \dfrac{H(L + W)}{6}\) oe	B1 B2
	(3)

Notes

B1: for \(N\) = expression with \(L, W, H\)

B2: for \(\dfrac{H(L + W)}{6}\) oe (B1 for \(\dfrac{L + WH}{6}\), \(L + \dfrac{WH}{6}\) etc)

Scheme	Marks
\(P = 2L + 2W\)	M1
\((N =) \dfrac{PH}{12}\)	A1
	(2)
	(5 marks)