Percentages: WJEC GCSE Numeracy Intermediate November 2020 Unit 1 Q12

Numeracy Intermediate November 2020 Unit 1 Q12

WJECIntermediateCurrent spec6 marksPercentages Standard Form Units & Time

12.

(a) A square piece of card measures 1 m by 1 m.

Calculate the area of this piece of card.
Give your answer in standard form in mm². [2]

…………… mm²

(b) Some fabric shrinks when it is washed.

A piece of fabric is washed twice.

After the first wash, the area of the fabric is 75% of the area of the original piece of fabric.
After the second wash, the area of the fabric is 90% of the area of the fabric after the first wash.

After these two washes, the area of the fabric is 2700 cm².

Calculate the area of the original piece of fabric. [4]

Mark scheme (a)

Scheme	Marks	Comments
\(1 \times 10^{6}\) (mm²)	B2	Allow \(10^{6}\) (mm²) B1 for any one of the following a calculated area 1 000 000 (mm²), \(1000^{2}\), \((10^{3})^{2}\) or equivalent ‘their clearly written number’ written correctly in standard form

Mark scheme (b)

Scheme	Marks	Comments
2700 ÷ (0.)9(0) or equivalent ÷ (0.)75 or equivalent	M1 M1	M marks can be awarded in either order Sight of 2700 ÷ (0.9 × 0.75) is awarded M2
4000 (cm²)	A2	A1 for 2700 ÷ 0.9 = 3000 or 2700 ÷ 0.75 = 3600 or for 2700 ÷ 0.675 or for an appropriate FT division correctly evaluated (Note: sight of 2700 ÷ 0.675 is awarded M2 A1)