# 10th Maths Paper Solutions Set 3 : CBSE All India Previous Year 2009

General Instructions:
1. All questions are compulsory.
2. The question paper consists of 30 questions divided into four sections - A, B, C and D. Section A comprises of ten questions of 1 mark each, Section B comprises of five questions of 2marks each, Section C comprises of ten questions of 3 marks each and Section D comprises of five questions of 6marks each.
3. All questions in Section A are to be answered in one word, one sentence or as per the exact requirement of the question.
There is no overall choice. However, an internal choice has been provided in one question of 2 marks each, three questions of 3 marks each and two questions of 6 marks each. You have to attempt only one of the alternatives in all such questions.
4. In question on construction, the drawing should be neat and as per the given measurements.
5. Use of calculators is not permitted.
Q1 :

Find the discriminant of the quadratic equation For the quadratic equation ax2 + bx + c = 0,

Discriminant = D =b2 − 4ac

Hence, for the given equation, D = = 100 − 36

= 64

Thus, the discriminant of the given equation is 64.

Q2 :

If , a, and 2 are three consecutive terms of an A.P., then find the value of a.

If three terms a, b, and c are in A.P., then we have ba = cb

⇒ 2b = a + c

∴ If are three consecutive terms of an A.P., then Thus, the value of a is .

Q3 :

If the areas of two similar triangles are in the ratio 25:64, write the ratio of their corresponding sides.

We know thatthe ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding sides.

It is given that the areas of two similar triangles are in the ratio 25:64. Thus, the ratio of the corresponding sides of the two similar triangles is 5:8.

Q4 :

In figure 1, ΔABC is circumscribing a circle. Find the length of BC. Q5 :

Two coins are tossed simultaneously. Find the probability of getting exactly one head.

Q6 :

Find the [HCF × LCM] for the numbers 100 and 190.

Q7 :

If 1 is a zero of the polynomial p(x) = ax2 − 3(a − 1) x − 1, then find the value of a.

Q8 :

If sec2θ (1 + sin θ) (1 − sin θ) = k, then find the value of k.

Q9 :

If the diameter of a semicircular protractor is 14 cm, then find its perimeter.

Q10 :

Find the number of solutions of the following pair of linear equations:

x + 2y − 8 = 0

2x + 4y = 16

Q11 :

If the points A (4, 3) and B (x, 5) are on the circle with the centre O (2, 3), find the value of x.

Q12 :

Which term of the A.P. 4, 12, 20, 28, … will be 120 more than its 21st term?

Q13 :

If , then evaluate OR

Find the value of tan 60°, geometrically.

Q14 :

Find all the zeroes of the polynomial x3 + 3x2 − 2x − 6, if two of its zeroes are and .

Q15 :

In Figure 2, ΔABD is a right triangle, right-angled at A and AC BD. Prove that AB2= BC . BD. Q16 :

Prove that is an irrational number.

Q17 :

Draw a right triangle in which sides (other than hypotenuse) are of lengths 8 cm and 6 cm. Then construct another triangle whose sides are times the corresponding sides of the first triangle.

Q18 :

Two dice are thrown simultaneously. What is the probability that

(i) 5 will not come up on either of them?

(ii) 5 will come up on at least one?

(iii) 5 will come up at both dice?

Q19 :

In Figure, 3, AD ⊥ BC and BD CD. Prove that 2CA2 = 2AB2 + BC2. OR

In Figure 4, M is mid-point of side CD of a parallelogram ABCD. The line BM is drawn intersecting AC at L and AD produced at E. Prove that EL = 2 BL. Q20 :

The sum of first six terms of an arithmetic progression is 42. The ratio of its 10thterm to its 30thterm is 1 : 3. Calculate the first and the thirteenth term of the A.P.

Q21 :

The area of an equilateral triangle is cm2. Taking each angular point as centre, circles are drawn with radius equal to half the length of the side of the triangle. Find the area of triangle not included in the circles. [Take = 1.73]

OR

Figure 5 shows a decorative block which is made of two solids − a cube and a hemisphere. The base of the block is a cube with edge 5 cm and the hemisphere, fixed on the top, has a diameter of 4.2 cm. Find the total surface area of the block. [Take π= ] Q22 :

Find the ratio in which the point (x, −1) divides the line segment joining the points (−3, 5) and (2, −5). Also find the value of x.

Q23 :

Find the area of the quadrilateral ABCD whose vertices are A (1, 0), B (5, 3), C (2, 7) and D (­−2, 4)

Q24 :

Evaluate:  Q25 :

Solve for x and y: ax by= 2ab

OR

The sum of two numbers is 8. Determine the numbers if the sum of their reciprocals is Q26 :

A juice seller serves his customers using a glass as shown in Figure 6. The inner diameter of the cylindrical glass is 5 cm, but the bottom of the glass has a hemispherical portion raised which reduces the capacity of the glass. If the height of the glass is 10 cm, find the apparent capacity of the glass and its actual capacity. (Use π= 3.14) OR

A cylindrical vessel with internal diameter 10 cm and height 10.5 cm is full of water. A solid cone of base diameter 7 cm and height 6 cm is completely immersed in water. Find the volume of

(i) water displaced out of the cylindrical vessel.

(ii) water left in the cylindrical vessel.

[Take π ]

Q27 :

Prove that the tangent at any point of a circle is perpendicular to the radius through the point of contact.

Using the above, do the following:

In Figure 7, O is the centre of the two concentric circles. AB is a chord of the larger circle touching the smaller circle at C. Prove that AC = BC. Q28 :

A 1.2 m tall girl spots a balloon moving with the wind in a horizontal line at a height of 88.2 m from the ground. The angle of elevation of the balloon from the eyes of the girl at that instant is 60°. After some time, the angle of elevation reduces to 30°. Find the distance travelled by the balloon during the interval.

Q29 :

Solve the following equation for x:

9x2− 9(a+ b)x+ (2a2+ 5ab + 2b2) = 0

OR

If (−5) is a root of the quadratic equation 2x2+ px − 15 = 0 and the quadratic equation p(x2+ x) + k= 0 has equal roots, then find the values of pand k.

Q30 :

During the medical check-up of 35 students of a class their weights were recorded as follows:

 Weight (in kg) Number of students 38 − 40 3 40 − 42 2 42 − 44 4 44 − 46 5 46 − 48 14 48 − 50 4 50 − 52 3

Draw a less than type and a more than type ogive from the given data. Hence obtain the median weight from the graph.