If and , then the LCM of and is:
- (A)
- (B)
- (C)
- (D)
Solution · answer (D)
- LCM takes each prime at its highest power: , and . LCM .
Answer: (D)
Report an error on this questionThe official board paper (Q.P. Code 430/3/1, Series EF3GH). Free paper PDF and step-by-step solutions (also as a PDF to download) written by CogniGuru and checked against CBSE’s answer key. See the paper’s main topics in 1 minute, then quiz yourself to see how much you know and where you stand.
No login to download or read the solutions. Login only to see your quiz report in full.
Three pages of the official paper. Download the PDF for all 27.
Your tutor walks you through the paper before you attempt it: the marks, the key ideas, the time plan and the traps.
1-minute paper analysis
With your tutor, in her voice
A short, animated walk through the paper: how it is built, where the marks come from, the four ideas that matter most, how to plan your three hours, and the traps to avoid.
Sound on for the voice. Captions are shown, and you can mute any time.
Try each question first, then open its solution. Tap a number to jump.
20 questions, 1 mark each. MCQs (Q1 to Q18) and assertion-reason (Q19, Q20).
If and , then the LCM of and is:
Answer: (D)
Report an error on this question, where is a natural number, cannot end with the digit:
Answer: (B) 5
Report an error on this questionA prime number has:
Answer: (B) exactly one prime factor
Report an error on this questionFor what value(s) of does the system of equations and have a unique solution?
If , is expressed as a quadratic equation in the form , then the value of is:
If point is the mid-point of the line segment joining the points and , then
The distance of point from -axis is:
Answer: (B) 3
Report an error on this questionThe value of is:
Which types of triangles are always similar?
Answer: (D) Equilateral triangles
Report an error on this questionWhat values of and will make similar to in the figures given below?

In the given figure, from which point can the tangent **not** be drawn to the circle with radius ?

Answer: (D) Y
Report an error on this questionIn the given figure, the angle of elevation of point from point is:

The angle of the sector of a circle whose area is one-eighth of the area of the circle is:
The perimeter of a quadrant of a circle of circumference 22 cm is:
A cone and cylinder have same height and same radius. The volume of the cone and the volume of the cylinder are in the ratio:
The following table shows the marks scored by 23 students of a class (marks 0–10, 10–20, 20–30, 30–40, 40–50 with 5, 3, 4, 8, 3 students). The lower limit of the modal class is:
| Marks | 0–10 | 10–20 | 20–30 | 30–40 | 40–50 |
|---|---|---|---|---|---|
| Number of Students | 5 | 3 | 4 | 8 | 3 |
Answer: (C) 30
Report an error on this questionFor a distribution, if mean = 15 and mode = 12, then its median is:
A pair of dice is thrown simultaneously. Let E denote the event that “The sum of numbers obtained on both dice is at least 9.” The number of outcomes in favour of event E is:
Assertion (A): For , must be .
Reason (R): .
Answer: (C) A is true, but R is false
Report an error on this questionAssertion (A): Every quadratic equation has two real roots.
Reason (R): A quadratic polynomial can have at most two zeroes.
Answer: (D) A is false, but R is true
Report an error on this question5 questions, 2 marks each.
Solve the following system of equations graphically: and .
Answer: ,
Report an error on this question(a) A vertical pole of height m casts a shadow of m on the ground and at the same time, a tower casts a shadow of m on the ground. Find the height of the tower.
OR
(b) In the given figure, and . Prove that .

Answer: (a) m (b) proved
Report an error on this questionIn the given figure, and are two tangents. If , then find the measure of .

Answer:
Report an error on this question(a) If , then find the value of .
OR
(b) If , then find the value of .
In the given figure, is a quadrant of a circle with centre and radius cm. If cm and cm, find the area of the shaded region. (Use )

Answer: cm²
Report an error on this question6 questions, 3 marks each.
(a) Prove that is an irrational number.
OR
(b) Find which among the following numbers , and is/are composite numbers. , , .
Answer: (a) proved (b) and are composite
Report an error on this questionFind the zeroes of the polynomial and verify the relationship between the zeroes and the coefficients of the given polynomial.
Answer: Zeroes ; relations verified
Report an error on this question(a) A fraction becomes , when is subtracted from the numerator and it becomes , when is added to its denominator. Find the fraction.
OR
(b) Find the value of for which the following pair of linear equations will have infinitely many solutions: and . Hence, find any two solutions of the given pair of equations.
Answer: (a) (b) ; solutions and
Report an error on this questionProve that:
A box contains 6 blue, 4 white and 8 red marbles. A marble is drawn at random from this box. Find the probability that the marble so drawn is:
(i) white
(ii) white or red
(iii) not red
In the given figure, a circle is inscribed in a quadrilateral which touches the sides , , and at , , and respectively. Prove that .

Answer: Proved
Report an error on this question4 questions, 5 marks each.
(a) Find two consecutive odd integers, sum of whose squares is .
OR
(b) A charity trust decides to build a rectangular hall having an area of m². The length of the hall is one metre more than twice its width. Find the length and breadth of the hall.
Answer: (a) and (also and ) (b) length m, breadth m
Report an error on this question(a) State and prove “Basic Proportionality Theorem”.
OR
(b) In the given figure, and are respectively the medians of and . If , prove that: (i) (ii) (iii)

Answer: Proved (both parts)
Report an error on this questionA perfume bottle is in the form of a cylinder but the bottom of the bottle has a hemispherical raised portion to reduce the capacity of the bottle. The inner diameter of the bottle is cm and the height of the bottle is cm. Find the capacity of the perfume bottle in mL. (Use and mL)

Answer: About mL
Report an error on this questionThe weights of 30 students of a class are given in the following distribution table:
Find the median weight of the students.
| Weight (in kg) | 40–45 | 45–50 | 50–55 | 55–60 | 60–65 | 65–70 |
|---|---|---|---|---|---|---|
| Number of students | 2 | 5 | 8 | 6 | 6 | 3 |
Answer: kg
Report an error on this question3 case studies, 4 marks each.
Case study 1. In a society, a yoga instructor was hired to train the people of the society to live a healthy lifestyle. Yoga sessions were held daily from 5 p.m. to 7 p.m. in the society park. On day one, 5 people joined the yoga session, on day two, 3 more people joined, on day three, another 3 people joined and in this manner every next day, 3 more people kept on joining.
Based on the given information, answer the following questions:
(i) On which day did 59 people join the yoga session? [1]
(ii) How many people joined the yoga session on the 31st day? [1]
(iii) (a) The yoga instructor was paid ₹ 100 for each person attending the yoga session. On which day would he earn ₹ 5,000? [2]
OR
(iii) (b) What was the total amount earned by the yoga instructor in 16 days? [2]
Answer: (i) day (ii) people (iii)(a) day (iii)(b) ₹
Report an error on this questionCase study 2. Two motorboats A and B are waiting at the opposite banks of a river in order to reach the opposite side. From a point P on the bridge, 20 m above the river, the angles of depression of the boats are 30° and 45° respectively, as shown in the figure given below. Both the boats leave at the same time at the speed of 10 m/s and 5 m/s, respectively.
Based on the above information, answer the following questions:
(i) Find the distance travelled by boat A to reach point D in the river, vertically below the point P. (Use √3 = 1.73) [1]
(ii) What is the width of the river? [1]
(iii) (a) Which boat will reach point D first, and how much earlier, than the other boat? [2]
OR
(iii) (b) What is the distance between the two boats after 3 seconds? [2]

Answer: (i) m (ii) m (iii)(a) boat A, s earlier (iii)(b) m
Report an error on this questionCase study 3. There is a semicircular park in Aman’s society. He wishes to plant saplings along the boundary of the park. There is a borewell at the centre O of the park along the diameter AB as shown in the figure below. A(2, 3), B(22, 3) and C(12, y).
Based on the above information, answer the following questions:
(i) Find the coordinates of point O. [1]
(ii) Find the radius of the semicircular park. [1]
(iii) (a) One sapling is kept at point C(12, y). Find the coordinates of C. [2]
OR
(iii) (b) One sapling is kept at point P along AB so that . Find the coordinates of P. [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
Q8, Q12, Q19, Q24, Q29, Q37 (12 marks): standard values and the identity sin² + cos² = 1.
How to remember trig values at 0°, 30°, 45°, 60°, 90° — Class 10Triangles
Q9, Q10, Q22, Q33 (9 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 nothingQuadratic Equations
Q5, Q20, Q32 (7 marks): the discriminant, standard form and solving by factorising.
Why does a quadratic have at most two real roots? — Class 10Statistics
Q16, Q17, Q35 (7 marks): mean, median and mode of grouped data.
Mean vs Median vs Mode — why one outlier can lie to youReal Numbers
Q1, Q2, Q3, Q26 (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 10Linear Equations
Q4, Q21, Q28 (6 marks): solving a pair of equations, graphing it, and when a pair is consistent.
When do two linear equations have no solution? — Class 10Coordinate Geometry
Q6, Q7, Q38 (6 marks): the distance, mid-point and section formulas.
Why is the distance formula just Pythagoras? — Class 10Midpoint Formula vs Section Formula — Class 10Circles
Q11, Q23, Q31 (6 marks): a tangent is perpendicular to the radius, and tangents from one point are equal.
Why is a tangent perpendicular to the radius? — Class 10Probability
Q18, Q30 (4 marks): favourable outcomes over total outcomes, and sure events.
Why is probability always between 0 and 1? — Class 10Arithmetic Progressions
Q36 (4 marks): the nth term and the sum of n terms.
Arithmetic vs Geometric Progression — why doubling always wins eventuallyPolynomials
Q27 (3 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 10Stuck on a step in any solution?
The CogniGuru AI tutor explains any doubt one minute at a time, in English or Hindi. Join the waitlist.
Five real questions from this paper, one each from five chapters. About 2 minutes. See how much you know and where you stand among other students. Attempt free, with no login; log in only for your ranking and full report.
, where is a natural number, cannot end with the digit:
0 of 5 answered