The units digit of 2 The total number of different A 3-digit number has x as its units digit; A company makes solid blocks with square bases. In an alien language, jalez borg farn means “good maths skills”. Nurf klar

6 ANSWER: E Let Q then P because APQ is isosceles ∧ ∧ = = y y , , ∆ QA C A C B Alternate interior angles AQ BC but A C B = 60 ABC is equilateral Q A C = 60 ∧ ∧ ∧ ∧ = ∴ || D D ∆ ∴ = + + ∴ = − ∴ = − 180 2 2 60 2 120 2 60 D D D D y x y x y x

11. The units digit of 2

2 2 2000 2001 2002 + + is A B C D E 2 4 6 8 ANSWER: B 2 2 2 2 1 2 2 2 7 2 2 2 4 8 2 16 2 4 8 6 2 2 2 6 7 42 2000 2001 2002 2000 2 2000 2 4 2000 4 2000 + + = + + = ∈ = = = = = × = . , , ; ; ; ; ; ; , , The number N has only the following possibilities for its unit digit: 2 2 i.e. and Since for some this number has 6 as its unit digit. Multiplying with 7, yields hence 2 as its unit digit. 1 3 x n x n 7

12. The total number of different

triangles in the diagram, including ∆ ABC , is A B C D E 21 42 63 84 105 ANSWER: C Count all the different triangles. Work with a plan, say from the smallest to the biggest: e.g. only some of the triangle sizes Top row triangles: X6 X5 X4 X3 X2 X1 Second row triangles: X6 … etc. X6 … etc. up to X1 If all the different triangles have been identified and calculated, you get 63 different triangles. B C A 8

13. A 3-digit number has x as its units digit;

x − 1 as the tens digit and 1 2 x as its hundreds digit. The number in terms of x is A B C D E 5 1 7 1 111 1 61 10 5 2 1 x x x x x − − − − − ANSWER: D 3 10 1 100 1 2 10 10 50 61 10 − + − + = + − + = − digit number: x x x x x x x .

14. A company makes solid blocks with square bases.

The volume of this block is 640 cm 3 . Its height is 10 cm. The cost of painting all the faces of this block at 15c per cm 2 is A R64,00 B R67,20 C R70,40 D R73,60 E R60,20 ANSWER: B Volume: V area of base area of base area of base Area of base length of base length of base 64 Surface area of block base area base perimete Cost: R = × ∴ = × = = = × ∴ = × ∴ = = × + × ∴ = × + × ∴ = + ∴ = ∴ × = h cm cm cm cm cm cm l l l cm S r h S cm S cm S cm c 640 10 640 10 64 8 2 2 64 32 10 128 320 448 448 15 67 20 3 3 2 2 2 2 2 : [ ] [ ] , 10 cm 9

15. In an alien language, jalez borg farn means “good maths skills”. Nurf klar

borg means “maths in harmony” and darko klar farn means “good in gold”. What is “harmony gold” in this language? A klar darko B borg nurf C jalez klar D darko nurf E farn borg ANSWER: D a jalez borg farn good maths skills b Nurf klar borg maths in harmony c darko klar farn good in gold From a and b: borg maths From b and c: klar in nurf harmony From a and c: farn good Hence darko gold Also, from all the above, the sentences are translated in reverse order, e.g. the last word in the alien language becomes the first word in English. “harmony gold” darko nurf 10 PART C: Each correct answer is worth 6 marks

16. As a result of poor attendance at soccer matches it was decided to decrease