MARKING SCHEME

2008 Autumn Paper 1 (Non calculator)Intermediate Tier20. 4x ≥ – 22 OR equivalent21. 131222.x ≥ – 22/4 (I.S.W.) (–5·5)52(4x – 1) – (2x + 7) = × 628x – 2 – 2x – 7 = 156x = 24x = 24/6 I.S.W. (= 4)23. (a) largest = 18 = (1·5)largest 12middle = 15 = (1·5)middle 10smallest = 9 = (1·5)smallest 6(All same ratio, therefore similar triangles)(b) For example, QR = 1510 12RQ = 12·5 (cm)MarksB2B13B22M1M1A1A14B2M1A1POST CONFERENCE MARK SCHEME (10/11/2008)Comments (Page 4)B1 for each side provided there is a correct inequality sign.F.T. until 2 nd error.F.T. equivalent difficulty if B1 has been awarded.0 marks if they only use = sign. Condone use of the > sign.For all 4 correct.B1 for any 3 correct.Must clear fractions by a valid methodFor handling 2 of the 3 terms correctlyFor the Ms, 2x+ 7 is acceptable, but the first A mark is A0.For handling all 3 terms correctlyCollecting terms. F.T. until 2 nd error if at least M1 awardedUnsupported answer of x = 4 gets all 4 marks.B1 for finding any 2 corresponding ratiosB2 for ‘The triangles have been multiplied by 3/2 OR 2/3’OR‘the scale factor is 3/2 OR 2/3’, etcOR‘both cancel to 3:5:6’ – must be all 3 correct values.Any correct equation with only QR unknownC.A.O.424. (a)3 2 and on the first branch5 5B1C.A.O.2 and 97 on the second branches9B1C.A.O. Accept only on one branch provided the other branch isempty.(b)2 7 ×5 9=1445M1A14F.T. their tree if probabilities are between 0 and 1 exclusive andNOT all ½.4