The HCF of smallest -digit number and the smallest composite number is:
- (A)2
- (B)20
- (C)40
- (D)4
Solution · answer (A)
- The smallest -digit number is and the smallest composite number is . HCF .
Answer: (A) 2
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20 questions, 1 mark each. MCQs (Q1 to Q18) and assertion-reason (Q19, Q20).
The HCF of smallest -digit number and the smallest composite number is:
Answer: (A) 2
Report an error on this questionThe value of ‘’ for which the pair of linear equations and has infinitely many solutions, is:
Which of the following equations has 2 as a root?
In an A.P., if and , then the first term ‘’ is equal to:
The distance of the point from the origin is:
If , then value of is:
is equal to:
is equal to:
A quadratic polynomial, the sum of whose zeroes is −5 and their product is 6, is:
The zeroes of the polynomial are:
The annual rainfall record of a city for 66 days is given in the following table. The difference of upper limits of modal and median classes is:
| Rainfall (in cm) | 0–10 | 10–20 | 20–30 | 30–40 | 40–50 | 50–60 |
|---|---|---|---|---|---|---|
| Number of days | 22 | 10 | 8 | 15 | 5 | 6 |
Answer: (C) 20
Report an error on this questionIf denotes the probability of an event , then:
Answer: (C)
Report an error on this questionThe total surface area of a solid hemisphere of radius cm is:
The difference of the areas of a minor sector of angle and its corresponding major sector of a circle of radius cm, is:
Answer: (B) cm²
Report an error on this questionThe graph of a pair of linear equations and in two variables and represents parallel lines, if:
Answer: (D)
Report an error on this questionIn the given figure, tangents and from a point to a circle with centre are inclined to each other at an angle of . is equal to:

A line intersecting a circle in two distinct points is called a:
Answer: (A) secant
Report an error on this questionIf a pole m high casts a shadow m long on the ground, then the sun’s elevation is:
Assertion (A): A line drawn parallel to any one side of a triangle intersects the other sides in the same ratio.
Reason (R): Parallel lines cannot be drawn to any side of a triangle.
Answer: (C) A is true, but R is false
Report an error on this questionAssertion (A): The point lies on -axis.
Reason (R): The -coordinate of a point, lying on -axis, is zero.
Answer: (A) Both A and R are correct and R is the correct explanation of A
Report an error on this question5 questions, 2 marks each.
Find the HCF of 84 and 144 by prime factorisation method.
(a) The sum of two natural numbers is and their difference is . Find the natural numbers.
OR
(b) Solve for and : and .
Answer: (a) and (b) ,
Report an error on this question15 defective pens are accidentally mixed with 145 good ones. One pen is taken out at random from this lot. Determine the probability that the pen taken out is a good one.
(a) In the given figure, . Prove that .
OR
(b) In the given figure, and . Prove that is isosceles.

Answer: Proved (both parts)
Report an error on this questionProve that the tangents drawn at the ends of a diameter of a circle are parallel to each other.
Answer: Proved
Report an error on this question6 questions, 3 marks each.
Two dice are tossed simultaneously. Find the probability of getting (a) an even number on both the dice. (b) the sum of two numbers more than 9.
Answer: (a) (b)
Report an error on this question(a) In two concentric circles, a chord of length cm of larger circle touches the smaller circle, whose radius is cm. Find the radius of the larger circle.
OR
(b) Prove that the angle between the two tangents drawn from an external point to a circle is supplementary to the angle subtended by the line segment joining the points of contact at the centre.
Answer: (a) cm (b) proved
Report an error on this questionProve that is an irrational number, given that is an irrational number.
Answer: Proved
Report an error on this question(a) Zeroes of the quadratic polynomial are and . Construct a quadratic polynomial whose zeroes are and .
OR
(b) Find the zeroes of the polynomial and verify the relationship between the zeroes and the coefficients.
Answer: (a) (b) zeroes ; relations verified
Report an error on this questionProve that .
A car has two wipers which do not overlap. Each wiper has a blade of length 21 cm sweeping through an angle of 120°. Find the area cleaned at each sweep of the blades.
Answer: cm²
Report an error on this question4 questions, 5 marks each.
A cottage industry produces a certain number of toys in a day. The cost of production of each toy (in rupees) was found to be 55 minus the number of toys produced in a day. On a particular day, the total cost of production was ₹ 750. Find the total number of toys produced on that day.
Answer: or toys
Report an error on this questionA TV tower stands vertically on a bank of a canal. From a point on the other bank exactly opposite the tower, the angle of elevation of the top of the tower is . From another point m away from this point on the line joining this point to the foot of the tower, the angle of elevation of the top of the tower is . Find the height of the tower and the width of the canal. [Use ]
Answer: Height m; width of the canal m
Report an error on this question(a) In the given figure, altitudes and of intersect each other at the point . Show that (i) (ii) (iii) .
OR
(b) and are medians of triangles and , respectively, where . Prove that .

Answer: Proved (both parts)
Report an error on this question(a) A textile industry runs in a shed. This shed is in the shape of a cuboid surmounted by a half cylinder. If the base of the industry is of dimensions and the height of the cuboidal portion is m, find the volume of air that the industry can hold. Further, suppose the machinery in the industry occupies a total space of m³. Then, how much space is left in the industry?
OR
(b) From a solid cylinder of height cm and radius cm, a conical cavity of the same height and same radius is carved out. Find the total surface area of the remaining solid. (Take )

Answer: (a) m³ of air; m³ left (b) cm²
Report an error on this question3 case studies, 4 marks each.
Case study 1. Saving money is a good habit and it should be inculcated in children right from the beginning. Rehan’s mother brought a piggy bank for Rehan and puts one ₹ 5 coin of her savings in the piggy bank on the first day. She increases his savings by one ₹ 5 coin daily.
Based on the above information, answer the following questions:
(i) How many coins were added to the piggy bank on 8th day? [1]
(ii) How much money will be there in the piggy bank after 8 days? [1]
(iii) (a) If the piggy bank can hold one hundred twenty ₹ 5 coins in all, find the number of days she can contribute to put ₹ 5 coins into it. [2]
OR
(iii) (b) Find the total money saved, when the piggy bank is full. [2]

Answer: (i) coins (ii) ₹ (iii)(a) days (iii)(b) ₹
Report an error on this questionCase study 2. Heart Rate: The heart rate is one of the ‘vital signs’ of health in the human body. It measures the number of times per minute that the heart contracts or beats. While a normal heart rate does not guarantee that a person is free of health problems, it is a useful benchmark for identifying a range of health issues. Thirty women were examined by doctors of AIIMS and the number of heart beats per minute were recorded and summarized as follows:
Based on the above information, answer the following questions:
(i) How many women are having heart beat in the range 68 – 77? [1]
(ii) What is the median class of heart beats per minute for these women? [1]
(iii) (a) Find the modal value of heart beats per minute for these women. [2]
OR
(iii) (b) Find the median value of heart beats per minute for these women. [2]
| Heart beats per minute | 65–68 | 68–71 | 71–74 | 74–77 | 77–80 | 80–83 | 83–86 |
|---|---|---|---|---|---|---|---|
| Number of women | 2 | 4 | 3 | 8 | 7 | 4 | 2 |

Answer: (i) (ii) (iii)(a) (iii)(b)
Report an error on this questionCase study 3. The top of a table is hexagonal in shape. On the basis of the information given in the figure (a grid on which the points A to T are marked), answer the following questions:
(i) Write the coordinates of A and B. [1]
(ii) Write the coordinates of the mid-point of line segment joining C and D. [1]
(iii) (a) Find the distance between M and Q. [2]
OR
(iii) (b) Find the coordinates of the point which divides the line segment joining M and N in the ratio 1 : 3 internally. [2]

Answer: (i) , (ii) (iii)(a) (iii)(b)
Report an error on this questionQuestions are from the official CBSE paper. Figures are described in words; see the PDF for the originals. Solutions are written by CogniGuru.
Each chapter below is what the paper tested, with a one-minute animated lesson on the idea behind it.
Trigonometry
Q6, Q7, Q8, Q18, Q30, Q33 (12 marks): standard values and the identity sin² + cos² = 1.
How to remember trig values at 0°, 30°, 45°, 60°, 90° — Class 10Triangles
Q19, Q24, Q34 (8 marks): similarity criteria, matching angles by sides, and the Basic Proportionality Theorem.
Why are two equal angles enough to prove triangles similar (AA)? — Class 10Congruence vs Similarity — why equal angles alone prove nothingCircles
Q16, Q17, Q25, Q27 (7 marks): a tangent is perpendicular to the radius, and tangents from one point are equal.
Why is a tangent perpendicular to the radius? — Class 10Real Numbers
Q1, Q21, Q28 (6 marks): HCF and LCM, rational and irrational numbers, and proofs of irrationality.
Rational vs Irrational Numbers — is 22/7 actually equal to π?Why is √2 irrational? The proof — Class 10Quadratic Equations
Q3, Q32 (6 marks): the discriminant, standard form and solving by factorising.
Why does a quadratic have at most two real roots? — Class 10Coordinate Geometry
Q5, Q20, Q38 (6 marks): the distance, mid-point and section formulas.
Why is the distance formula just Pythagoras? — Class 10Midpoint Formula vs Section Formula — Class 10Probability
Q12, Q23, Q26 (6 marks): favourable outcomes over total outcomes, and sure events.
Why is probability always between 0 and 1? — Class 10Arithmetic Progressions
Q4, Q36 (5 marks): the nth term and the sum of n terms.
Arithmetic vs Geometric Progression — why doubling always wins eventuallyPolynomials
Q9, Q10, Q29 (5 marks): zeroes, their sum and product, and reading zeroes from a graph.
Why is the sum of zeroes −b/a and the product c/a? — Class 10Statistics
Q11, Q37 (5 marks): mean, median and mode of grouped data.
Mean vs Median vs Mode — why one outlier can lie to youLinear Equations
Q2, Q15, Q22 (4 marks): solving a pair of equations, graphing it, and when a pair is consistent.
When do two linear equations have no solution? — Class 10Stuck on a step in any solution?
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The HCF of smallest -digit number and the smallest composite number is:
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