the average of first 21 natural number is 11 find the average of first 20 natural number
Answers
1. If m is a positive integer which is not a perfect square, then the value of √m is:
(a) A natural number (b) An irrational number (c) An integer (d)A rational number
2. X = -4, Y = 2 is a solution of the linear equation:
(a) X - Y = 7 (b) 5X + 2Y = -2 (c) X + Y = -2 (d) 5X - 2Y = 7
3. The factors of 2X2
-7X + 3 are:
(a) (X - 3)(2X - 1) (b) (X + 3)(2X + 1) (c) (X - 3)(2X + 1) (d) (X + 3)(2X - 1)
4. The distance of the point (4, -3) from X – axis is:
(a) 3 unit (b) 4 unit (c) -3 unit (d) -4 unit
5. The length of a chord in a circle of radius 15 cm is 24 cm. The distance of this chord from the
centre of circle is:
(a) 5 cm (b) 7 cm (c) 9 cm (d) 11 cm
Very short answer type:
1. Find the total surface area of cone, if its slant height is 21 cm and the diameter of base is 24 cm.
2. Write the constant term in the expansion of (X + 7)
2
.
3. In which quadrants, abscissa of a point is negative?
4. If the graph line of 2X + KY = 6K intersects X axis at (-3, 0), find the value of K.
5. Using Heron’s formula, find the area of an equilateral triangle of side 1 cm.
SECTION – B 2X3=6
6. Prove that “Equal chords of a circle subtend equal angle at the centre”.
7. The sides of a triangular plot are in the ratio 3 : 5 : 7 and its perimeter is 300 m. Find its area.
8. In which quadrant, do the given points lie? (i) (-3, -1) (ii) (7, -2) (iii) (-8, 9) (iv) (5, 6)
SECTION – C 3X4=12
9. Represent √8.7 geometrically on number line.
10. Factorise 2X3 – 3X2 – 17X + 30.
11. The taxi fare in a city is as follows: For the first kilometer, the fare is Rs. 20 and for the subsequent
distances it is Rs. 10 per Km. Taking the distances covered as X Km and total fare as Rs. Y, write a
linear equation for the information, and draw its graph.
12. A cube of side 21 cm contains a sphere touching its sides. Find the volume of gap in between.
SECTION – D 4X3=12
13. If the non parallel sides of a trapezium are equal, prove that it is cyclic.
14. The sides of a triangular field are 41 m, 40 m and 9 m. Find the number of rose beds that can be
prepared in the field if each rose bed, on an average needs 900 cm2
space.
15. 30 circular plates, each of radius 14 cm and thickness 3 cm are placed one above the another to form a
cylindrical solid.
Find: (i) Total surface area of obtained solid (ii) Volume of the obtained solid