Averages (including IQR): WJEC GCSE Intermediate June 2025 Unit 1 Q15

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Intermediate June 2025 Unit 1 Q15

WJECIntermediateCurrent spec4 marksAverages (including IQR)

15. The mean of five whole numbers is 20.

The mean of three of these numbers is 22.
The other two numbers have a difference of 6.

Find the other two numbers. [4]

Mark scheme

Scheme	Marks	Comments
5 × 20 OR 3 × 22 or equivalent	M1	Award M1 for exclusively finding five values with a sum of 100 OR three values with a sum of 66.
100 AND 66	A1	May be seen or implied in later working. An exclusive appropriate sight of 100 AND 66 implies M1 A1 (do not award the M1 A1 for 100 and 66 seen along with other totals unless 100 and 66 used in further workings).
(100 – 66 =) 34	B1	May be seen or implied in later working. FT ‘their 5 × 20’ – ‘their 3 × 22’.
14 and 20	B1	Mark final answer. FT to find two values with a difference of 6 for ‘their 34’, provided M1 previously awarded. Award B1 for sight of 14 and 20 along with three other values that total 66. Unsupported 14 and 20 is awarded M1 A1 B1 B1.