TOPPER SAMPLE PAPER 5 Summative Assessment-II MATHEMATICS CLASS X M.M: 80 TIME : 3-3 1 Hrs. 2 GENERAL INSTRUCTIONS : 1. 2. 3. 4. All questions are compulsory. The question paper consists of 34 questions divided into four sections, namely Section A : 10 questions (1 mark each) Section B : 8 questions (2 marks each) Section C : 10 questions (3 marks each) Section D : 6 questions (4 marks each) There is no overall choice. However, internal choice has been provided in 1 question of two marks, 3 questions of three marks and 2 questions of four marks each. Use of calculators is not allowed. SECTION A Q1. If x=b is a solution of x2- (a + b) x + p=0, then the value of p is (a) ab Q2. (b) a + b (c) a-b (d) a b The ratio of the volume of a cube to that of a sphere which will exactly fit inside the cube is (a) :8 (b) (c) 8: (d) 6: Q3. If A (1,2) , B (4,y), c (x,6) and D (3,5) are the vertices of a parallelogram taken in order then the values of x and y are (a) (b) (c) (d) Q4. 6 and 5 6 and 3 2 and 3 5 and 2 In a lottery there are 5 prizes and 20 blanks. The probability of getting a prize is (a) Q5. 1 2 (b) 1 3 (c) 1 4 (d) 1 5 If x silver coins 1.75 cm in diameter and of thickness 2 mm, must be melted to form a cuboid 11cmx10cmx7cm, then the value of x is (a) 1200 Q6. 1600 (d) 1800 (b) 450 (c) 300 (d) 900 In given AP 210 is ............. term: 2,6,10........ (a) 50th Q8. (c) PQ is a tangent drawn from a point P to a circle with centre O and QOR is a diameter of the circle such that POR=1200, then OPQ is (a) 600 Q7. (b) 1400 (b) 52nd (c) 53rd (d) 54th A kite is flying, attached to a thread which is 165m long. The thread makes an angle of 300 with the ground. The height of the kite from the ground, assuming that there is no slack in the thread is (a) 80 m (b) 81.5 m (c) 82.5 m (d) 84 m Q9. The points (a, b + c), (b, c + a) and (c, a + b) are (a) Collinear (b) Non-collinear (c) Concurrent (d) All of the above Q10. If the area of a circle is 154 cm 2, then its perimeter is (a) 11cm (b) 22cm (c) 44cm (d) 55cm SECTION B Q11. Find the area of a square ABCD, whose vertices are A(5,6), B(1,5), C(2,1) and D(6,2). Q12. Q13. Q14. The height of a right triangle is 7 cm less than its base. If the hypotenuse is 13 cm, find the other two sides. Prove that the angle between two tangents drawn from an external point to a circle is supplementary to the angle subtended by the line segments joining the points of contact at the centre. The minute hand of a clock is 10 cm long. Find the area of the face of the clock described by the minute hand between 9AM and 9:35 AM. Q15. Four equal circles are described about the four corners of a square so that each touches two of the others as shown in figure. Find the area of the square not included in the circles if each side of the square measures 14cm. Q16. A number x is selected from the numbers 1, 2, 3 and then a second number y is randomly selected from the numbers 1, 4, 9. What is the probability that the product xy of the two numbers will be less than 9? OR Three unbiased coins are tossed together. Find the probability of getting atmost two tails. Q17. Q18. Determine the 10th term from the end of the AP 4,9,14,........,254. Show that the tangents at the end points of a diameter of a circle are parallel. SECTION C Q19. The area of a triangle is 5. Two of its vertices are (2, 1) and (3,-2) and the third vertex lies on y=x+3. Find the third vertex. Q20. If the roots of the equation (a-b)x2+(b-c)x+(c-a)=0 are equal then prove that 2a=b+c. OR Solve : Q21. 1 1 1 1 a b x abx Draw a pair of tangents to a circle of radius 5cm which are inclined to each other at angle of 600. Also, write the steps of construction. OR Construct a ABC in which AB = 4 cm, BC = 5 cm and AC = 6 cm. Then, CA BA BC 2 construct a triangle ABC such that . CA BA BC 3 Q22. The m th term of an AP is n and the n th term is m. find the sum of (m + n) terms. Q23. Two pillars of equal height are on either side of a road, which is 100m wide. The angles of elevation of the top of the pillars are 60 0 and 300 at a point on the road between the pillars. Find the height of the pillars. OR As observed from the top of a lighthouse, 100 metres high above sea level, the angle of depression of a ship moving directly towards it, changes from 30 o to 60o. Determine the distance travelled by the ship during the period of observation. Q24. Find the coordinates of the vertices of a ∆ABC with A (1,-4) and the mid point of sides through A being (2,-1) and (0,-1). Q25. One card is drawn from a well shuffled pack of 52 cards. Calculate the probability of getting (i) A king or a queen (ii) Neither a heart nor a red king Q26. Find the area of the shaded region if PQ=24cm, PR=7cm and O is the centre of the circle. Q27. An iron pole consisting of a cylindrical portion 110cm high and of base diameter 12cm is surmounted by a cone 9cm high. Find the mass of the pole, given that 1cu cm of iron has 8 gm mass (approx.) Q28. Water flows at the rate of 10m per minute through a cylindrical pipe having its diameter as 5mm. how much time will it take to fill a conical vessel whose diameter of base is 40cm and depth is 24cm? SECTION D Q29. Prove that the coordinates of the centroid of a triangle whose vertices are x x2 x3 y1 y2 y3 (x1,y1),(x2,y2)and (x3,y3) is given by 1 , . 3 3 Q30. A vertical tower stands on a horizontal plane and is surmounted by a vertical flagstaff of height h. At a point on the plane, the angles of elevation of the bottom and the top of the flagstaff are and β respectively. Prove that the tan height of the tower is h . tan tan Q31. By increasing the list price of a book by Rs10, a person can buy 10 less books for Rs.1200. Find the original list price of the book. OR Two years ago a man’s age was three times the square of his son’s age. Three years hence his age will be four times his son’s age. Find their present ages. Q32. Prove that the lengths of tangents drawn from an external point to a circle are equal. OR Prove that the radius of a circle is perpendicular to the tangent at the point of contact. Q33. A circle is touching the side BC of ∆ABC at P and touching AB and AC produced at Q and R respectively. Prove that AQ = Q34. 1 (perimeter of ∆ABC). 2 A bucket is in the form of a frustum of a cone of height 30 cm with radii of its lower and upper ends as 10 cm and 20 cm, respectively. Find the capacity and surface area of the bucket. Also, find the cost of the milk which can completely fill the container, at the rate of Rs 25 per litre (use = 3.14). SOLUTIONS SECTION A Ans1. Option (a) ab Given x=b therefore it satisfies the given equation b2-(a + b) b+p=0 p=ab Ans2. Option (d) 6: Let x be the edge of cube. Then, x is also the diameter of the sphere. Ratio of the volume of the cube to the volume of sphere = x3 : 4 x3 4 1: 6: 3 8 24 Ans3. Option (b) 6 and 3 We know that the diagonals of a parallelogram bisect each other. So, coordinates of mid point of AC = coordinates of mid point of BD. x 1 6 2 3 4 5 y 2 , 2 2 , 2 x 1 7 5 y 2 ,4 2 , 2 x 1 7 5y and 4 2 2 2 X=6 and y=3. Ans4. Option (d) 1 5 5 prizes and 20 blanks Total number of outcomes = 25 Number of favourable outcomes =5 P(getting a prize) = 5 1 25 5 Ans5. Option (c) 1600 Required number of coins = = volume of cuboid volume of eachcoin 770 7 22 0.875 0. 875 .2 = 40x40 =1600 Ans6. Option (c) 300 Ans7. Option (c) 53rd an=a+(n-1)d 210=2+(p-1)4 4(p-1)=208 P-1=52 P=53 Hence 53rd term is 210. Ans8. Option (c) 82.5 m Let A be the position of the kite. Let O be the observer and OA be the thread. Given, OA =165m, BOA = 300 and let AB = h m. In right ∆OBA, AB OA = sin30 h 1 165 2 h= 165 = 82.5 2 Thus, the height of the kite from the ground is 82.5 m. Ans9. Option (a) collinear Area of a triangle = 1 [{a(c+a)+b(a+b)+c(b+C)}-{b(b+c)+c(c+a)+a(a+b)}] 2 = 1 [ac+a2+ab+b2+bc+c2-b2-bc-c2-ca-a2-ab] 2 = 1 (0) = 0 2 Since, the area of triangle is 0, therefore, the given points are collinear. Ans10. Option (c) 44cm Area of a circle = πr2 154 = 22 2 r 7 r2=49 or r=7 perimeter = 2πr = 2x 22 x 7 = 44cm. 7 SECTION B Ans11. In a square, all the sides are equal. So, AB=BC=CD=DA Distance AB= 1 52 (5 6)2 17 units 1 mark Area of Square ABCD = AB 2 = 17 2 = 17 sq. Units. 1 mark Ans12. let base = x cm and height = (x – 7) cm Hypotenuse = 13 cm By Pythagoras theorem, X2 + (x – 7)2 = 132 X2 + 49 + x2 – 14x = 169 2x2 – 14x – 120 = 0 X2 – 12x + 5x – 60 = 0 1 mark 2 X( x – 12) + 5 (x – 12) = 0 1 mark 2 (x – 12) (x + 5) = 0 x – 12 = 0 or x + 5 = 0 x=12 or x=-5 (rejecting) The other two sides are 12 cm and 5 cm. 1 mark 2 1 mark 2 Ans13. Let PA and PB be two tangents drawn from an external point P to a circle with centre O. We have to prove that angles AOB and APB are supplementary i.e. AOB+ APB=1800. In right triangles OAP and OBP, we have PA=PB (tangents drawn from an external point to a circle are equal in length) OA=OB (radii of same circle) OP=OP (common) ∆OAP ∆OBP (by SSS) OPA= OPB and AOP= BOP (by cpct) 1 mark APB = 2 OPA and AOB =2 AOP But, AOP=90- OPA 2 AOP =180-2 OPA AOB =180- APB AOB+ APB=180 1mark Ans14. Angle described by the minute hand in 1 minute=60 Angle described by the minute hand in 35 minutes =6x35=2100 Area swept by the minute hand in 35 minutes= 210 22 x (10)2 360 7 = 183.3 cm2. Ans15. Area of the square = (14)2 = 196 cm2 1 mark 2 1 mark 1 mark 2 1 mark 2 Area of four quadrants = area of one circle = πr 2 = 22 x (7)2 =154 cm2 7 Required area = 196-154 = 42 cm2. 1 mark 1 mark 2 Ans16. Number x can be selected in three ways and corresponding to each such way there are three ways of selecting number y. therefore,the two numbers can be selected in 9 ways as listed below: (1,1),(1,4),(1,9),(2,1),(2,4),(2,9),(3,1),(3,4),(3,9) Total number of outcomes =9 1 mark The product xy will be less than 9, if x and y are chosen in one of the following ways: 1 mark 2 (1,1),(1,4),(2,1),(2,4), (3,1) Number of favourable outcomes =5 P(product less than 9) = 1 mark 2 5 . 9 OR S=[HHH,HHT,HTH,THH,HTT,THT,TTH,TTT] Total number of outcomes = 8 1 mark 2 At most two tails = HHH, HHT, HTH, THH, HTT, THT, TTH Number of favourable outcomes =7 P(at most two tails) = 1 mark 1 mark 2 7 8 Ans17. L= last term =254 and d=5 Nth term from the end = l- (n-1)d 1 mark 2 1 mark 2 tenth term from the end = 254- (10-1)5 =254-45 = 209. 1 mark Ans18. 1 mark 2 Let AB be a diameter of a given circle, and let PQ and RS be the tangent lines drawn to the circle at points A and B respectively. Since tangent at a point to a circle is perpendicular to the radius through the point. Therefore, AB is perpendicular to both PQ and RS. PAB=90 and ABS =90 PAB= ABS But, these are a pair of alternate interior angles. Therefore, PQ is parallel to RS. 1 mark 1 mark 2 SECTION C Ans19. Let the third vertex be A(x, y). Other two vertices of the triangle are B(2,1) and C(3,-2). Area of ∆BC = 5 sq. Units 1 {x (1+2) + 2 (-2-y) + 3 (y-1)} = 5 2 1 mark 1 {3x-4-2y + 3y-3} = 5 2 {3x+ y-7} = ± 10 3x + y -17 = 0 (i) or 3x +y +3 = 0 (ii) 1 mark Given that, A(x, y) lies on y = x + 3 (iii) On solving (i) and (iii) we get, x = On solving (ii) and (iii) we get, x = 7 13 and y = and, 2 2 3 3 and y = . 2 2 1 mark Ans20. Here, (a-b)x2+(b-c)x+(c-a)=0 The given equation will have equal roots, if (b-c)2-4(a-b)(c-a)=0 1 mark b2+c2-2bc-4(ac-bc-a2+ab) =0 b2+c2+4a2+2bc-4ab-4ac=0 (b+c-2a) 2 =0 b+c-2a=0 1 mark b+c=2a 1 mark OR 1 1 1 1 a b x abx 1 1 1 1 a b abx x x (a b x) ab ab a b x x 1 mark a b ab ab a b x x ax+bx+x2=-ab x2+ax+bx+ab=0 x(x+a)+b(x+b)=0 (x+a)(x+b)=0 x+a=0 or x+b=0 1 mark x=-a,-b Ans21. The tangents on given circle as follows: 1 mark 1. Draw a circle of 5 cm radius and with centre O. 2. Take a point P on circumference of this circle. Extend OP to Q such that OP = PQ. 3. Midpoint of OQ is P. Draw a circle with radius OP with centre as P. Let it intersect our circle at R and S. Join QR and QS. QR and QS are required tangents. 1 mark 2 marks OR CA BA BC 2 . This CA BA BC 3 means that the triangle ABC is similar to the triangle ABC with scale factor as 2 . 3 ABC is the required triangle. A triangle ABC is to be constructed such that 3 marks Ans22. Here, And, a+(m-1)d =n …………(i) a+(n-1)d =m ………..(ii) 1 mark On solving (i) and (ii), we get, d = -1 and a= m+n-1 Sm+n= Ans23. mn mn [2(m+n-1) + (m+n-1)(-1)] = (m+n-1) 2 2 1 mark 1 mark 1 mark 2 Let AB and CD be two pillars of equal heights, say, h metres. Let P be a point on road such that AP= x m and PC = 100 –x. APB= 600 and CPD =300. In right ∆PAB, AB AP Tan60 = 3 h x h 3x ……….. (1) 1 mark In right ∆PCD, tan30 = 1 3 CD PC h 100 x …………….(2) 1 mark 2 From (1) and (2) we get, 3x=100-x or x=25 From (1) , h=25 3 1 mark Thus, the height of the pillars is 25 3 metres. OR 1 mark 2 Let A and B be the two positions of the ship. Let d be the distance travelled by the ship during the period of observation, i.e., AB=d metres. Suppose that the observer is at the point P. given that PC = 100m. Let h be the distance (in metres) from B to C. From right triangle PCA, we have dh cot 30 3 100 d+h = 100 3 ..(i) Again in triangle PCB, we have, h 1 cot 60 100 3 1 mark h= 100 3 metres. 1 mark 2 Putting the value of h in (i) we get, 200 1 d= 100 3 = 115.47 (approx.) = 3 3 Thus, the distance travelled by the ship from A to B is 115.47 m(approx.) 1 mark Ans24. Let the coordinates of A, B and C be (1, -4), (a, b) and (x, y) resp. 1 a 4 b Then, = (2,-1) , 2 2 1 mark Therefore, 1+a=4, -4+b= -2 a=3, b=2 1 mark 1 x 4 y Also, = (0,-1) , 2 2 Therefore, 1+x=0, -4+y= -2 x= -1 , y=2 Therefore, the coordinates of the vertices of ∆ABC are A (1,-4), B (3, 2) and C (-1, 2) Ans25. Total number of outcomes =52 (i) Number of kings = 4 Number of queens = 4 1 mark 4 4 8 2 52 52 13 (ii) Number of cards of hearts =13 P(king or queen) = 1 marks 2 1 Number of red kings =2 ( out of these 1 is already in hearts) Neither a heart nor a red king = 52 – (13+2-1) =52-14 =38 P(neither a heart nor a red king) = 38 19 52 26 1 1 marks 2 Ans26 . In ∆QPR, by Pythagoras theorem, we have, QR2=PR2+PQ2 = 72+242=49+576=625 QR=25cm Diameter of the circle = 25cm Radius of the circle = Area of semicircle = 25 2 r2 22 25 25 11 625 cm2 2 2722 28 1 mark Area of ∆PQR = 1 1 PR PQ 7 24 84 cm2 2 2 Area of shaded region = 1 mark 11 625 6875 2352 4523 84 28 28 28 = 161.54 cm2 1 mark Ans27. Volume of the pole = volume of the cylinder + volume of the cone 1 = 62 110 62 9 cu cm 3 1 mark = [3960+108] cu cm = 4068 cu cm 1 mark Mass of the pole = 4068 x3.14x8 = 102188.16 grams = 102.19 kg 1 mark Ans28. Amount of water required to fill the conical vessel = volume of the conical vessel = 2 1 40 (24) cu cm =3200 cu cm ……….(i) 3 2 1 mark Amount of water that flows out of the cylindrical pipe in 1 minute 2 5 = (10x100) = 62.5 cu cm …………..(ii) 20 1 mark From (i) and (ii) , we get, Time taken to fill the vessel = 3200 minutes = 51.2 minutes 62.5 1 mark SECTION D Ans29. 1 mark 2 Let A(x1,y1), B(x2,y2) and C(x3,y3) be the vertices of ∆ABC whose medians are AD,BE and CF respectively. So, D,E and F are respectively the mid points of BC,CA and AB. 1 mark x x2 y3 y2 Coordinates of D are 3 , 2 2 1 mark 2 Coordinates of a point G(x, y) dividing AD in the ratio 2 : 1 are 1 mark 2 2( ( ( x 2 x3 y y3 ) x1 2( 2 ) y1 2 2 , ) 2 1 2 1 1 mark x1 + x 2 x3 y1 + y 2 y3 , ) 3 3 1 mark 2 Ans30. 1 mark Let AB be the tower and BC be the flagstaff. Let OA=x metres, AB= y metres and BC= h metres. In right ∆OAB, Tan = AB OA In right ∆OAC, y x tan or x y ………………………..(i) tan 1mark Tanβ = yh x x y h tan ………………………………….(ii) 1mark From (i) and (ii), y h y tan tan y( tanβ y= - tan ) = h tan h tan tan tan Thus, the height of the tower is h tan . tan tan Ans31. Let list price of the book = Rs x And increased price of the book = Rs (x+10) According to question, 1200 1200 =10 x x 10 1 mark 1 mark 1 1 (1200) =10 x x 10 x 10 x =10 (1200) x x 10 1 mark 2 1200=x(x+10) x2+10x-1200=0 (x+40)(x-30)=0 X=-40 X=30 But x is the cost of the book and hence can’t be negative. Therefore x=30 1 mark 1 mark 1 mark 2 List price of book=Rs 30 OR Two years ago, let son’s age = x years Therefore man’s age = 3x2 Three years hence, son’s age = x+2+3=(x+5) years and man’s age = 3x2+5 By the given condition 3x2+5=4(x+5) 1 mark 3x2-4x+5-20=0 3x2-4x-15=0 1 mark 2 3x -9x+5x-15=0 3x(x-3)+5(x-3)=0 (x-3)(3x+5)=0 x=3 [Because 3x+5=0 means x = 5 , not possible) 3 1 mark Therefore son’s present age = x+2=3+2=5 years Man’s present age = 3x2+2=3(3)2+2 = 27+2=29 years 1 mark Ans32. Given: A circle with centre O; PA and PB are two tangents to the circle drawn from an external point P. To prove: PA = PB Construction: Join OA, OB, and OP. 2 marks It is known that a tangent at any point of a circle is perpendicular to the radius through the point of contact. OA PA and OB PB ... (1) In OPA and OPB: OAP = OBP (Using (1)) OA = OB (Radii of the same circle) OP = PO (Common side) Therefore, OPA OPB (RHS congruency criterion) PA = PB (Corresponding parts of congruent triangles are equal) Thus, it is proved that the lengths of the two tangents drawn from an external point to a circle are equal. 2 marks OR Given: A circle C (O, r) and a tangent AB at a point P. To Prove: OP is perpendicular to AB. Construction: Take any point Q, other than P, on the tangent AB. Join OQ. 2 marks Since, Q is a point on the tangent AB, other than the point of contact P, so Q will be outside the circle. Let OQ intersect the circle at R. Then, OQ=OR+RQ OQ>OR (OR=OP=radius) OQ>OP Thus, OP<OQ, i.e., OP is shorter than any other segment joining O to any point of AB. But, among all the line segments, joining the point O to a point on AB, the shortest one is the perpendicular from O on AB. Hence, OP is perpendicular to AB. 2 marks Ans33. 1 mark Since tangents from an exterior point to a circle are equal in length. BP=BQ (From B) ..............(i) CP=CR (From C) ...............(ii) And, AQ=AR (From A) ..........(iii) From (iii) we have, 1 mark AQ=AR AB+BQ=AC+CR AB+BP=AC+CP ...........(iv) Perimeter of ∆ABC = AB+BC+CA = AB+(BP+PC)+AC = (AB+BP) + (AC+PC) = 2(AB+BP) = 2(AB+BQ) = 2AQ 1 (perimeter of ∆ABC). AQ = 2 Ans34. Capacity (or volume) of the bucket = 1 mark h [r21 + r22 + r1r2] 3 Here, h = 30 cm, r1 = 20 cm and r2 = 10 cm So, the capacity of bucket = 3.14 x 1 mark 1 mark 2 30 [202 + 102 + 20 x 10] cm3 3 = 21980 cu cm = 21.980 litres. 1 mark Cost of 1 litre of milk = Rs 25 Cost of 21980 litres of milk = Rs 21.980 x 25 = Rs 549.50 Surface area of the bucket 1 mark 2 = curved surface area of the bucket + surface area of the bottom = l(r1 + r2) + r22 Now, l = where l= h2 (r1 r2 )2 900 100 cm = 31.62 cm 1 mark 2 1 mark 2 Therefore, surface area of the bucket = 3.14 x 31.62 (20+10) + 3.14x 102 = 3.14 x 1048.6 cm2 = 3292.6 cm2 (approx.) 1 mark
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