Kerala SSLC Board Question Papers for Class 10th Maths 2019 With Solutions In PDF

Kerala SSLC or Class 10 Maths Question Paper 2019 with Answers – Free Download

Kerala SSLC (Class 10) maths 2019 question paper with solutions are provided here in a downloadable pdf format and also in the text so that the students can easily access them. Along with the solutions, they can also get the maths question paper 2019 class 10 sslc for reference. Students are able to access all the Kerala board previous year maths question papers here. SSLC question paper 2019 kerala for English medium with answers can be downloaded easily and students can practice and verify the answers provided by BYJU’S. Solving 2019 Maths question papers for class 10 will help the students to predict what type of questions will appear in the exam.

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QUESTION PAPER CODE S 1935

Kerala Class 10 Examination Question Paper Solutions March 2019
Kerala Class 10 Examination Question Paper Solutions March 2019 1
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Answer any three questions from 1 to 4. Each question carries 2 scores. [3 * 2 = 6]

Question 1: In the figure, O is the centre of the circle. ∠AOC = 80o

[i] What is the measure of ∠ABC?

[ii] What is the measure of ∠ADC?

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 1

Given ∠AOC = 800

[i] The measurement ∠ABC = (1 / 2) * ∠AOC = 1 / 2 × 80 = 400.

[ii] ∠ABC + ∠ADC = 180o

40o. + ∠ADC = 180o

∠ADC = 180o – 40o

∠ADC = 140o

Question 2: [i] Write the first integer term of the arithmetic sequence (1 / 7), (2 / 7), (3 / 7) …….

[ii] What is the sum of the first 7 terms of the above sequence?

Solution:

[i] Given arithmetic sequence = 1 / 7 + 2 / 7 + 3 / 7 ,………..

Common difference d = 2 / 7 – 1 / 7 = 1 / 7.

Hence the first integer term = 7 / 7 = 1

[ii] a = (1 / 7)

d = 2 / 7 – 1 / 7

= 1 / 7

n = 7

Sn = (n / 2) (2a + [n – 1]d)

S7 = (7 / 2) (2 * [1 / 7] + [7 – 1] * [1 / 7])

= (7 / 2) ([2 / 7] + 6 * (1 / 7))

= (7 / 2) ([2 / 7] + [6 / 7])

= (7 / 2) (8 / 7)

= 4

Question 3: [i] If C (-1, k) is a point on the line passing through the points A (2, 4) and B (4, 8) which number is k?

[ii] What is the relation between the x coordinate and the y coordinate of any point on this line?

Solution:

[i] Kerala Class 10 Maths Question Paper 2019 Question Number 3a

Points A, B and C are collinear.

Area of triangle ABC = 0

(1 / 2) (x1 [y2 – y3] + x2 [y3 – y1] + x3 [y1 – y2])

|2 (8 – k) + 4 (k – 4) + (-1) (4 – 8)| = 0

16 – 2k + 4k – 16 – 4 + 8 = 0

2k = -4

k = -2

[ii]

Kerala Class 10 Maths Question Paper 2019 Question Number 3b

Area of triangle ABP = 0

(1 / 2) (x1 [y2 – y3] + x2 [y3 – y1] + x3 [y1 – y2])

|2 (8 – y) + 4 (y – 4) + (x) (4 – 8)| = 0

16 – 2y + 4y – 16 – 4x = 0

2y – 4x = 0

2y = 4x

y = 2x

2x – y = 0

Question 4: [i] Find P(1) if P(x) = x2 + 2x + 5

[ii] If (x – 1) is a factor of x2 + 2x + k, what is the value of k?

Solution:

[i] P(x) = x2 + 2x + 5

P(1) = 12 + 2 * 1 + 5

= 1 + 2 + 5

P(1) = 8

[ii] Since (x – 1) is the factor of x2 + 2x + k, then

x – 1 = 0

x = 1

(1)2 + 2(1) + k = 0

1 + 2 + k = 0

k = -3

Answer any five questions from 5 to 11. Each question carries 3 scores. [5 * 3 = 15]

Question 5: [i] What is the remainder on dividing the terms of the arithmetic sequence 100, 107, 114 ….. by 7?

[ii] Write the sequence of all three-digit numbers. Which leaves the remainder 3 on division by 7? Which is the last term of this sequence?

Solution:

[i] Given sequence be 100, 107, 114, ………..

d = 7

Remainder = 100 / 7 = 2

[ii] 101, 108, 115 ……………..

Hence the last three-digit term = 997.

Question 6: AB is the diameter of the circle. D is the point on the circle.

Kerala Class 10 Maths Question Paper 2019 Question Number 6

∠ACB + ∠ADB + ∠AEB = 270o. The measure of one among ∠ACB, ∠ADB and ∠AEB is 110o. Write the measures of ∠ACB, ∠ADB, ∠AEB.

Solution:

∠ADB = 900 ( Measurement of semi circle angle)

∠ACB + ∠ADB + ∠AEB = 2700 (given)

∠ACB + 90o + ∠AEB = 2700

∠ACB + ∠AEB = 2700 – 90o = 1800

The given condition is that any one of the angles ∠ACB, ∠AEB be 1100.

Take ∠ACB = 1100

Hence ∠AEB = 180o – 110o = 700

So the angles , ∠ADB = 900 , ∠ACB = 1100 , ∠AEB = 700.

Question 7: If x is a natural number,

[a] What number is to be added to x2 + 6x to get a perfect square?

[b] If x2 + ax + 16 is a perfect square number, then which number is a?

[c] If x2 + ax + b is a perfect square, prove that a2 = 4b.

Solution:

Given x2 + 6x

[a] 6x = 2ab

a = x

b = ?

b = 6x / 2x = 3

Perfect square = b2 = 32 = 9.

Hence 9 is to be added to them.


[b] Given, x2 + ax + 16 is perfect square

This is the form of a2 + 2ab + b2 = (a + b)2

2ab = ax

a = x

b2 = 16

b = √16 = 4

So, (x + 4)2 = x2 + ax + 16

Hence a = 2ab = 2 × 4 = 8.

[c] Here b = the square of the half of a

b = (a / 2)2

b = a2 / 4

a2 = 4b

Question 8: In the figure, ∠B = 90o, ∠C = 44o.

Kerala Class 10 Maths Question Paper 2019 Question Number 8

[a] What is the measure of A?

[b] Which among the following is tan 44o:

(AB / BC) , (AB / AC), (BC / AB), (BC / AC)

[c] Prove that tan 44o * tan 46o = 1

Solution:

[a] ∠A + ∠B + ∠C = 180o

∠A + 90o + 44o = 180o

∠A = 180o – 90o – 44o

∠A = 46o

[b] In triangle ABC,

tan 44o = opposite / adjacent

= AB / BC {from the figure}

[c] Take LHS = tan 44o * tan 46o

= tan 44o * cot (90o – 46o) [tan θ = cot (90 – θ)]

= tan 44o * cot 44o

= tan 44o * [1 / tan 44o]

= 1

= RHS

Question 9: Draw a circle of radius 3 centimetres. Mark a point P at a distance of 6cm from the centre of the circle. Draw tangents from P to the circle.

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 9

Steps of construction:

  • Draw a circle of radius 3cm with O as the centre.
  • From the centre O, draw OP = 6cm and perpendicular to OP marking it as M.
  • Draw another circle with centre M cutting T and R respectively.
  • Join PT and PR which are the required tangents.

Question 10: [i] Find the coordinates of the point on the x-axis, which is at a distance of 4 units from (3, 4).

[ii] Find the coordinates of the point on the x-axis at a distance of 5 units from (3, 4).

Solution:

[i]

Kerala Class 10 Maths Question Paper 2019 Question Number 10a

4 = √(x – 3)2 + (0 – 4)2

On squaring both sides,

42 = (x – 3)2 + 16

x – 3 = 0

x = 3

A (3, 0) is the required point.

Kerala Class 10 Maths Question Paper 2019 Question Number 10a

[ii]

Kerala Class 10 Maths Question Paper 2019 Question Number 10b

AB = 5

√(x – 3)2 + (0 – 4)2 = 5

On squaring both sides,

(x – 3)2 + 16 = 52

(x – 3)2 + 16 = 25

(x – 3)2 = 25 – 16

(x – 3)2 = 9

(x – 3) = ± 3

x – 3 = 6

x = 6

x – 3 = -3

x = 0

Hence, (6, 0) and (0, 0) is the required point.

Kerala Class 10 Maths Question Paper 2019 Question Number 10b

Question 11: The given figure is the lateral face of a square pyramid. AB = AC = 25 centimeters and BD = DC = 15 centimeters.

[i] What is the length of its base edge?

[ii] Find the lateral surface area of the pyramid.

Kerala Class 10 Maths Question Paper 2019 Question Number 11

Solution:

Side of the base = diagonal / √2

= (30 / √2) * (√2 / √2)

= 15 √2 cm

= 15 * 1.414

= 17.210

Side of the base = 17.210 cm

Lateral surface area = (1 / 2) * perimeter of the base * slant height

= (1 / 2) * (17.21) * 4 * 25

= 860.50 cm2

Answer any 7 questions from 12 to 21. Each question carries 4 scores. [7 * 4 = 28]

Question 12: In triangle ABC, ∠A = 30o, ∠B = 80o, the circumradius of the triangle is 4 centimetres. Draw the triangle. Measure the length of its smallest side.

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 12

Steps of construction:

  • Draw a circle of radius 4cm having a centre at O.
  • Make an angle ∠BOC = 60o.
  • Construct an angle ∠CBA = 80o.
  • Join AC.
  • △ABC is the required triangle.

∠A + ∠B + ∠C = 180o

30o + 80o + ∠C = 180o

∠C = 180o – 110o

∠C = 70o

30o < 70o < 80o

∠A < ∠C < ∠B

The smallest angle is ∠A.

BC is the smallest side of △ABC.

Question 13: Find the following sums:

[i] 1 + 2 + 3 + …… 100

[ii] 1 + 3 + 5 + …… 99

[iii] 2 + 4 + 6 + …… 100

[iv] 3 + 7 + 11 + ……. 199

Solution:

[i] 1 + 2 + 3 + …… 100

a = 1

d = 2 – 1 = 1

Last term = 100 = l

l = a + (n – 1) d

100 = 1 + (n – 1) 1

100 = 1 + n – 1

n = 100

Sn = (n / 2) (n + 1)

S100 = (100 / 2) (100 + 1)

= (50) * (101)

= 5050

[ii] 1 + 3 + 5 + …… 99

a = 1

d = 3 – 1 = 2

Last term = 99 = l

l = a + (n – 1) d

99 = 1 + (n – 1) 2

99 = 1 + 2n – 2

99 = 2n – 1

100 = 2n

100 / 2 = n

50 = n

Sn = (n / 2) (a + an)

S50 = (50 / 2) (1 + 99)

= (25) * (100)

= 2500

[iii] 2 + 4 + 6 + …… 100

a = 2

d = 4 – 2 = 2

Last term = 100 = l

l = a + (n – 1) d

100 = 2 + (n – 1) 2

100 = 2 + 2n – 2

100 = 2n

n = 100 / 2

n = 50

Sn = (n / 2) (a + an)

S50 = (50 / 2) (2 + 100)

= (25) * (102)

= 2550

[iv] 3 + 7 + 11 + ……. 199

a = 3

d = 7 – 3 = 4

Last term = 199 = l

l = a + (n – 1) d

199 = 3 + (n – 1) 4

199 = 3 + 4n – 4

199 = 4n – 1

200 / 4 = n

n = 50

Sn = (n / 2) (a + an)

S50 = (50 / 2) (3 + 199)

= (25) * (202)

= 5050

Question 14: A box contains some green and blue balls. 7 red balls are put into it. Now the probability of getting a red ball from the box is 7 / 24 and that of the blue ball is 1 / 6.

[i] How many balls are there in the box?

[ii] How many of them are blue?

[iii] What is the probability of getting a green ball from the box?

Solution:

Let the number of green balls be x.

The number of blue balls is y.

Number of red balls = 7

Total number of balls = x + y + 7

P (red ball) = 7 / 24

P (blue ball) = 1 / 3

[i] Since P(red ball) = 7 / 24,

7 / [x + y + 7] = 7 / 24

24 = x + y + 7

24 – 7 = x + y

17 = x + y —- (1)

P (blue ball) = 1 / 3

y / [x + y + 7] = 1 / 3

3y = x + y + 7

2y = x + 7

-x + 2y = 7 —- (2)

On adding equation (1) and (2),

17 = x + y

-x + 2y = 7

_______

3y = 24

y = 24 / 3

y = 8

Put y = 8 in equation (1),

17 = x + 8

17 – 8 = x

x = 9

Total number of balls = 8 + 9 + 7 = 24

[ii] Number of blue balls

y / 24 = 1 / 3

3y = 24

y = 8

[iii] P (green ball) = x / 24 = 9 / 24 = 3 / 8

Question 15: Land is acquired for road widening from a square ground, as shown in the figure. The width of the acquired land is 2 meters. Area of the remaining ground is 440 square meters.

Kerala Class 10 Maths Question Paper 2019 Question Number 15

[i] What is the shape of the remaining ground?

[ii] What is the length of the remaining ground?

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 15a

[i] The shape of the remaining ground is rectangular.

[ii] Let the length be x and breadth be x – 2.

Given,

Area = 440 m2

L * B = 440

x * (x – 2) = 440

x2 – 2x = 440

x2 – 2x – 440 = 0

(x – 22) (x + 20) = 0

x = 22 , -20

Since the values must be positive, x = 22 is taken.

Length = 22m

Breadth = 22 – 2 = 20m

Question 16: In the figure, P is the centre of the circle. A, B and D are points on the circle. ⦣P = 90o, AD = 5cm.

Kerala Class 10 Maths Question Paper 2019 Question Number 16

(a) What is the measure of ⦣A?

(b) What is the area of the triangle APD?

(c) Find the area of the parallelogram ABCD.

Solution:

[a] In triangle APD, ⦣P = 90o

⦣A = ⦣D [angle opposite to equal side are equal]

⦣A + ⦣ADP + ⦣APD = 180o [angle sum property of a triangle]

⦣A + ⦣A + 90o = 180o

2⦣A = 90o

⦣A = 45o

[b] In triangle APD,

sin 45o = PD / AD

1 / √2 = PD / 5

5 / √2 = PD = AP

Area of △ADP = (1 / 2) * AP * PD

= (1 / 2) * (5 / √2) * (5 / √2)

= 25 / 4 cm2

[c] Area of a parallelogram = base * height

= AB * PD

= 2AP * PD

= 2 * (5 / √2) * (5 / √2)

= 25 cm2

Question 17: [a] Draw the coordinates and mark the points A (1, 1), B (7, 1).

[b] Draw an isosceles triangle ABC with AB as the hypotenuse.

[c] Write the coordinates of C.

Solution:

[a]

Kerala Class 10 Maths Question Paper 2019 Question Number 17a

AC = BC

√(x – 1)2 + 1 = √(x – 7)2 + 1

On squaring both sides,

(x – 1)2 + 1 = (x – 7)2 + 1

x2 + 1 – 2x + 1 = x2 + 49 – 14x + 1

-2x + 14x = 49 – 1

12x = 48

x = 48 / 12

x = 4

[b]

Kerala Class 10 Maths Question Paper 2019 Question Number 17b

C (4, 0) is the required point.

Coordinate of C (4, 4) [AD = BC = CD]

The midpoint of the hypotenuse is equal distance from the vertex of the triangle.

Question 18: In the figure, chord BC is extended to P. Tangent from P to the circle is PA. AQ is the bisector of ⦣BAC.

Kerala Class 10 Maths Question Paper 2019 Question Number 18

[a] Write one pair of equal angles from the figure.

[b] If ⦣PAC = x and ⦣PCA = y, then prove that ⦣BAC = y – x.

[c] Prove that ⦣PAQ = [y +x] / 2

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 18

[a] ⦣BAC = ⦣PAC

[b] ⦣PAC = ⦣ABC

⦣ACP = ⦣BAC + ⦣ABC [exterior angle property]

y = ⦣BAC + x

⦣BAC = y – x

[c] ⦣PAQ = ⦣PAC + ⦣CAQ

= x + (1 / 2) * ⦣BAC

= x + (1 / 2) * (y – x)

= x + (1 / 2) y – (1 / 2) x

⦣PAQ = (1 / 2) (x + y)

Question 19: If (x – 1) is a factor of the second-degree polynomial P (x) = ax2 + bx + c and P(0) = -5.

[a] What is the value of c?

[b] Prove that a + b = 5.

[c] Write a second-degree polynomial whose one factor is x – 1.

Solution:

[a] Given that x – 1 is a factor of the polynomial ax2 + bx + c

x – 1 = 0

x = 1

P(1) = 0

a (1)2 + b * 1 + c = 0

a + b + c = 0 —- (1)

Now, at x = 0, P(0) = -5

a * 0 + b * 0 + c = -5

c = -5

[b] a + b + c = 0

a + b – 5 = 0

a + b = 5

[c] Second-degree polynomial = 3x2 + 2x – 5 or 2x2 – 3x + 5 or 4x2 + x – 5 [any of them]

Question 20: A circular sheet of paper is divided into two sectors. The central angle of one of them is 160o.

[a] What is the central angle of the remaining sector?

[b] These sectors are bent into cones of maximum volume. If the radius of the small cone is 8 centimetres, what is the radius of the other?

[c] What is the slant height of the cone?

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 20

[a] Central angle of the remaining sector = 360o – 160o = 200o

[b] R1 is the radius of the small cone = 8cm

2𝛑R1 = 2𝛑r (θ1) / 360o

8 = r * (160o / 360o)

r = (360o * 8) / 160o

r = 18cm

2𝛑R2 = 2𝛑r (θ2) / 360o

R2 = (18 * 200o) / 360o

R2 = 10cm

[c] Slant height (l1) = 18cm

Slant height (l2) = 18cm

Question 21: Equation of the line AB is 3x – 2y = 6. P is a point on the line. The line intersects the y-axis at A and the x-axis at B.

[a] What is the x coordinate of A?

[b] What is the length of OA?

[c] What is the length of OB?

[d] The x coordinate and the y coordinate of P are the same. Find the coordinates of P.

Kerala Class 10 Maths Question Paper 2019 Question Number 21

Solution:

Given, the equation of line AB is 3x – 2y = 6

x

0

2

y

-3

0

[a] x coordinate of A = 0

[b] OA = 3 units

[c] OB = 2 units

[d]

Kerala Class 10 Maths Question Paper 2019 Question Number 21d

A, B, P are collinear.

Area of △ABP = 0

(1 / 2) [0 (0 – x) + 2 (x + 3) + x (-3 -0)] = 0

2x + 6 – 3x = 0

x = 6

Hence, the coordinates of P are (6, 6).

Answer any 5 questions from 22 to 28. Each question carries 5 scores. [5 * 5 = 25]

Question 22: If the terms of the arithmetic sequence (2 / 9), (3 / 9), (4 / 9), (5 / 9), ……. Are represented as x1, x2, …. then

[a] x1 + x2 + x3 =

[b] x4 + x5 + x6 =

[c] Find the sum of the first 9 terms.

[d] What is the sum of the first 300 terms?

Solution:

[a] x1 + x2 + x3

= (2 / 9) + (3 / 9) + (4 / 9)

= 9 / 9

= 1

[b] x4 + x5 + x6

= (5 / 9) + (6 / 9) + (7 / 9)

= (18 / 9)

= 2

[c] n = 9

a = 2 / 9

d = (3 / 9) – (2 / 9) = (1 / 9)

Sn = (n / 2) (2a + [n – 1]d)

S9 = ( 9 /2) (2 * [2 / 9] + [9 – 1] * (1 / 9))

= (9 / 2) [(4 / 9) + (8 / 9)]

= (9 / 2) (12 / 9)

= 6

[d] n = 300

a = 2 / 9

d = (3 / 9) – (2 / 9) = (1 / 9)

Sn = (n / 2) (2a + [n – 1]d)

S300 = ( 300 /2) (2 * [2 / 9] + [300 – 1] * (1 / 9))

= (300 / 2) [(4 / 9) + (299 / 9)]

= (150) (303 / 9)

= 5050

Question 23: Draw a rectangle of area 12 square centimetres. Draw a square having the same area.

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 23

For the given rectangle,

Area = 12cm2

x * y = 12cm2

For a square, x = y.

x * x = 12cm2

x2 = 12cm2

x = 2√3 cm

Kerala Class 10 Maths Question Paper 2019 Question Number 23

Question 24: A boy standing at one bank of a river sees the top of a tree on the other bank directly opposite to the boy at an elevation of 60o. Stepping 40 meters back, he sees the top of the elevation at 30o.

[a] Draw a rough sketch and find the height of the tree.

[b] What is the width of the river?

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 24

Let AB be h and CB be x.

In △ABC,

tan 60o = AB / BC

√3 = h / x

h = √3x —- (1)

In △ABD,

tan 30o = AB / BD

1 / √3 = h / x + 40

x + 40 = √3 (√3x) — (2)

x + 40 = 3x

40 = 2x

x = 20

h = 20√3 m

Width of the river is 20m and the height of the tree is 20√3m.

Question 25: Circle with centre O touches the sides of a triangle at P, Q and R, AB = AC, AQ = 4cm and CQ = 6cm.

Kerala Class 10 Maths Question Paper 2019 Question Number 25

[a] What is the length of CP?

[b] Find the perimeter and the area of the triangle.

[c] What is the radius of the circle?

Solution:

Kerala Class 10 Maths Question Paper 2019 Question Number 25

[a] CP = CQ [Length of external tangents are equal]

CP = 6cm

[b] Perimeter of triangle = 4 + 6 + 6 + 6 + 4 + 6 = 32 cm

For the area of △ABC,

s = [AB + BC + CA] / 2

= [10 + 12 + 10] / 2

= 16cm

Area of △ABC = √s (s – a) (s – b) (s – c)

= √(16) (16 – 10) (16 – 12) (16 – 10)

= √16 * 6 * 4 * 6

= 48cm2

[c] Area of △ABC = area of △AOB + area of △BOC + area of △COA

48 = (1 / 2) * 10 * r + (1 / 2) * 12 * r + (1 / 2) * 10 * r

48 * 2 = r (10 + 12 + 10)

48 * 2 = 32 * r

r = 3cm

Question 26: Radius of a cylinder is equal to its height. If the radius is taken as ‘r’, the volume of the cylinder is 𝛑r2 * r = 𝛑r3. Like this find the volumes of the solids, with the following measures.

Kerala Class 10 Maths Question Paper 2019 Question Number 26

[a] What is the ratio of the volumes of the cone, hemisphere, cylinder and the sphere?

[b] A solid metal sphere of radius 6cm is melted and recast into solid cones of radius 6cm and height 6cm. Find the number of cones.

Solution:

[a]

Kerala Class 10 Maths Question Paper 2019 Question Number 26a

[b] Vc : Vh : Vcy : Vs = [𝛑r3 / 3] : [2 / 3] 𝛑r3 : 𝛑r3 : [4 / 3] 𝛑r3

= (1 / 3) : (2 / 3) : 1 : (4 / 3)

= 1 : 2 : 3 : 4

Number of cones = Volume of the sphere / Volume of the cone

= [(4 / 3) 𝛑r3] / [𝛑R2h / 3]

= {[4 * 𝛑 * 63] / (3)} / {[𝛑 * 62 * 6] / (3)}

= 4

Question 27: C is at the centre of the circle passing through the origin. Circle cuts the y-axis at A (0, 4) and the x-axis at B(4, 0).

Kerala Class 10 Maths Question Paper 2019 Question Number 27

[a] Write the coordinates of C.

[b] Write the equation of the circle.

[c] (0, 0) is a point on the circle. There is one more point on the circle with x and y coordinates equal. Which is that?

Solution:

[a] C is the midpoint of AB.

x = [4 + 0] / 2

= 4 / 2

x = 2

y = [4 + 0] / 2

= 4 / 2

y = 2

The coordinates of C are (2, 2).

[b] The equation of the circle is given by (x – a)2 + (y – b)2 = r2

(x – 2)2 + (y – 2)2 = [√(4 – 2)2 + (0 – 2)2]2

x2 + 4 – 4x + y2 + 4 – 4y = 8

x2 + y2 – 4x – 4y = 0

[c] Let P(x, x) be a point on the circle.

x2 + x2 – 4x – 4x = 0

2x2 – 8x = 0

x = 0, 4

The required point is (4, 4).

Question 28: The table below shows the number of children in a class, sorted according to their heights.

Kerala Class 10 Maths Question Paper 2019 Question Number 28

If the students are directed to stand in a line according to the order of their heights starting from the smallest, then

[a] The height of the child at what position is taken as the median?

[b] What is the assumed height of the child in the 17th position?

[c] Find the median height.

Solution:

Class interval

frequency

Cumulative frequency

130 – 140

7

7

140 – 150

9

16

150 – 160

10

26

160 – 170

10

36

170 – 180

9

45

[a] N = 45

Median is taken as [N + 1] / 2

= [45 + 1] / 2

= 46 / 2

= 23

The height of the child at the 23rd position is taken as the median.

[b] Height of the child in the 17th position between 150 – 160. Assumed height is 152cm.

[c] Median = [l1] + {[(N / 2) – C] / cf} * h

= 150 + [22.5 – 16] / 10 * (10)

= 150 + 6.5

= 156.5

Question 29: Read the following. Understand mathematical concepts in it and answer the questions that follow.

The remainders obtained on dividing the powers of two by 7 have an interesting property.

We can understand it from the table given below.

Kerala Class 10 Maths Question Paper 2019 Question Number 29

If the powers are 1, 4, 7 ….. the remainder is 2.

If the powers are 3, 6, 9 ….. the remainder is 1.

[a] What is the remainder on dividing 28 by 7?

[b] Write the sequence of powers of 2 leaving remainder 1 on division by 7.

[c] Check whether 2019 is a term of arithmetic sequence 3, 6, 9 …….

[d] What is the remainder on dividing 22019 by 7?

[e] Write the algebraic form of the arithmetic sequence 1, 4, 7 ……

[f] Write the algebraic form of the sequence 21, 24, 27 ….. [powers of two leaving remainder 2 on division by 7].

Solution:

[a] If 28 is divided by 7, then the remainder is 7.

[b] 23, 26, 29 ……. when divided by 7 leaves a remainder 1.

[c] Yes

2019 = 3 (n – 1) 3

2019 = 3n – 9

2019 + 9 = 3n

2018 = 3n

2018 / 3 = n

n = 673 terms

[d] 1 is the remainder on dividing 22019 by 7.

[e] an = a + (n – 1)d

an = 1 + (n – 1)3

= 1 + 3n – 3

an = 3n – 2

[f] 1, 4, 7 ….. nth term is 3n – 2.

So, the algebraic form is 23n-2.

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