ANSWER KEY SESSION ENDING EXAMINATION Model Exam -1
Grade: VIII Subject: Mathematics Max.Marks: 50 Duration: 120 +15 Min
Chapters : Algebraic Expressions, Factorization, Exponents and Powers & Direct and Inverse proportions
SECTION-A (1 x 10 = 10)
1.(a) 12a3bc2
2.c) Rs. 13.00
3.d) 2x(1-4)(1+4x)
4.d) 7(a-3b)(a+3b)
5. c) 34/24
6.0.000532
7. 6
8. 240 MIN
9.(pq-1)(q+1)
10. 2x (3x + 5xy) =6x²+10x²y
SECTION-B (2x5=10 marks)
11. Add: 7xy + 5yz – 3zx, 4yz + 9zx – 4y , –3xz + 5x – 2xy.
12. State whether or not 2x + 3 is a factor of 6x3 +19x2 +13x – 3
2x+3=0
x=-3/2
Yes. 6(-3/2)³ -3 +19 (-3/2)² + 13(-3/2)
13. A train is moving at a uniform speed of 75 km/hour. (i) How far will it travel in 20 minutes? (ii) Find the time required to cover a distance of 250 km.
14. Evaluate : (6-1 – 7-1 )-1 – (5-1 – 4-1 )-1. ‘
= (⅙-1/7)^-1 x (⅕-¼)^-1= (1/42)x(1/-20) = (-840)
15. Find the factors of 16l2 + 24lm + 9m2. = (4l+3m)²
SECTION-C (3x5=15 marks)
16. Subtract: 3a (a + b + c ) – 2 b (a – b + c) from 4c ( – a + b + c )
Or
Simplify: 3y(2y – 7) – 3(y – 4) – 63 and evaluate for y = – 2.
17. Factorize the following expressions: a) x4 – (x – z)4 b) a4 – 2a²b² + b4
18.The vertical pole 5 m 60 cm high casts a shadow 3 m 20 cm long. Find at the same time (i) the length of the shadow cast by another pole 10 m 50 cm high (ii) the height of a pole which casts a shadow 5m long
19. A school has 8 periods a day each of 45 minutes duration. How long would each period be, if the school has 9 periods a day, assuming the number of school hours to be the same?
20.Express the number appearing in the following statements in standard form.
(i) Sun is located 300,000,000,000,000,000,000 m from the centre of our Milky Way.
3x 10^20 m
(ii) The distance between Sun and Saturn is 1,433,500,000,000 m = 1.4335 x 10^12
SECTION-D (5x3=15 marks)
21. Simplify:
(i) (a + b) (c – d) + (a – b) (c + d) + 2 (ac + bd) (3 marks)
(ii) (1.5x – 4y)(1.5x + 4y + 3) – 4.5x + 12y (2 marks)
22. (i) Factorise the expressions and divide them as directed. (3 marks)
(a) (5p2 – 25p + 20) ÷ (p – 1)
(b) 4yz(z2 + 6z – 16) ÷ 2y(z + 8)
(ii) Find the value of x for which
(2 marks)
23. (i) By what number should be divided that quotient is ? (2 marks)
(ii) Ramesh is making a wheel using spokes. He wants to x equal spokes in such a way that the angles between any pair of consecutive spokes are equal. Help him by completing the following table: (3 marks)
a) Are the number of spokes and the angles formed between the pair of consecutive spokes in inverse proportion?
b) Calculate the angle between a pair of consecutive spokes on a wheel with 15 spokes.
c) How many spokes would be needed if the angle between a pair of consecutive spokes is 40o?
