S3_Mock2_Paper2_2015_Sol_E.doc - Solution Solution 5 6 7 9...

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Solution Solution Mock Exam 2 (2015) Paper 2 Section A 1. D (3 x y ) 2 (3 x y ) 2 9 x 2 – 6 xy y 2 9 x 2 6 xy y 2 18 x 2 2 y 2 2. B 4 p 2 – 9 q 2 – 4 p 1 [(2 p ) 2 – 2(2 p )(1) 1 2 ] – 9 q 2 (2 p – 1) 2 (3 q ) 2 [(2 p – 1) – 3 q ][(2 p – 1) 3 q ] (2 p – 3 q – 1)(2 p 3 q – 1) 3. C For I, a > b ac 2 > bc 2 , since c 2 > 0 I is not true. For II, b > c a b > a c II is true. For III, a > b c a < c b , since c < 0 III is true. 4. A 5( x – 7) – 8 x 4 5 x – 35 – 8 x 4 3 x 39 x 13 5. D c b a 10 9 8 7 5 6 9 10 7 8 6 5 c b a 36 35 48 c b a b < c < a 6. B Interest 1 12 % 6 1 000 75 $ 18 $7045 (cor. to the nearest dollar) 7. B Quarterly rates of the flat $78 000 6% 4 $1170 8. C 2 rh 2 ) 2 ( π 4 2 1 r 2 rh 8 r 2 h r 4 1 r : h 1 : 4 9. B 5 6 of Radius of Radius 25 36 of Radius of Radius 2 B C B C B A of Volume of Volume 3 of Radius of Radius B A 3 of Radius of Radius of Radius of Radius B C C A 125 64 5 6 3 2 3 Volume of A : Volume of B 64 : 125 © Hong Kong Educational Publishing Company 1
New Progress in Junior Mathematics 3 (Second Edition) Mock Exam Papers 10. B Total surface area of the solid [4 (4) 2 2 (4)(6)] cm 2 112 cm 2 11. A 3 ) 2 ( π 3 4 r 12 r 2 h 8 r 3 9 r 2 h h r 8 9 r : h 9 : 8 12. C Let b cm and h cm be the base and the height of the parallelogram with AB as the base. Note that ABJ ~ GFJ (AAA) and BEK FHK (ASA) . AB GF ABJ GFJ of Height of Height 4 1 Height of GFJ with GF as the base h 4 1 1 cm h 5 1 cm Area of GFJ h b 5 1 4 1 2 1 cm 2 bh 40 1 cm 2 Area of FHK h b 2 1 2 1 2 1 cm 2 bh 8 1 cm 2 Area of GJKH bh bh 40 1 8 1 cm 2 12 bh 10 1 bh 120 The area of parallelogram ABCD is 120 cm 2 . 13. B Let V be the number of vertices of the polyhedron. Number of edges of the polyhedron 2 3 8 8 6 36 By Euler’s formula, V – 36 (6 8) 2 V 24 The number of vertices of the polyhedron is 24. 14. C Let r cm be the base radius of the circular cone. r 2 24 2 25 2 (Pyth. theorem) r 2 2 24 25 7 Volume of the circular cone ) 24 ( ) 7 ( π 3 1 2 cm 3 392 cm 3 15. D Refer to the following figure.

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