MATHEMATICS BASIC (241) SAMPLE QUESTION PAPER
SECTION A (MCQs & Assertion-Reason) 20 Marks
If HCF (2520, 6600) = 40 and LCM (2520, 6600) = 252 × k, then the value of k is:
HCF(a, b) × LCM(a, b) = a × b
Step-by-Step Substitution & Calculation:- Given: a = 2520, b = 6600, HCF = 40, LCM = 252 × k
- 40 × (252 × k) = 2520 × 6600
- 10080 × k = 16,632,000
- k = 2520 × 660040 × 252
- k = 10 × 660040 = 6600040 = 1650
If α and β are the zeroes of the polynomial 2x2 − 4x − 5, the value of (α − β)2 is:
α + β = −ba, αβ = ca, and (α − β)2 = (α + β)2 − 4αβ
Step-by-Step Substitution & Calculation:- For polynomial 2x2 − 4x − 5: a = 2, b = −4, c = −5
- α + β = −(−4)2 = 2
- αβ = −52
- (α − β)2 = (2)2 − 4×(−52) = 4 + 10 = 14
For what value of p does the pair of linear equations 4x + py + 8 = 0 and 2x + 2y + 2 = 0 have a unique solution?
Condition for unique solution: a1a2 ≠ b1b2
Step-by-Step Substitution & Calculation:- Here a1 = 4, b1 = p; a2 = 2, b2 = 2
- 42 ≠ p2
- 2 ≠ p2 ⇒ p ≠ 4
The sum of the numerator and denominator of a fraction is 11. If the denominator is increased by 1, the fraction becomes 12, then the fraction is:
Let fraction be xy. Given: x + y = 11 and xy + 1 = 12
Step-by-Step Substitution:- 2x = y + 1 ⇒ 2x − y = 1
- Adding (x + y = 11) and (2x − y = 1): 3x = 12 ⇒ x = 4
- y = 11 − 4 = 7
- Required Fraction = 47
If one root of the quadratic equation ax2 + bx + c = 0 is the reciprocal of the other, then:
Product of roots of ax2 + bx + c = 0 is ca
Step-by-Step Substitution:- Let roots be α and 1α
- Product of roots = α × 1α = 1
- ca = 1 ⇒ a = c
The first term of an AP is p and the common difference is q, then its 10th term is:
n-th term of an AP: an = a + (n − 1)d
Step-by-Step Substitution:- Given: a = p, d = q, n = 10
- a10 = p + (10 − 1)q = p + 9q
Which term of the AP: 21, 42, 63, 84 … is 210?
an = a + (n − 1)d
Step-by-Step Substitution:- a = 21, d = 42 − 21 = 21, an = 210
- 210 = 21 + (n − 1)21
- 189 = (n − 1)21 ⇒ n − 1 = 9 ⇒ n = 10
If the point P(5, 2) divides the line segment joining A(8, 5) and B(4, y) in the ratio 3 : 1, then the value of y is:
Section formula for y-coordinate: yP = m1y2 + m2y1m1 + m2
Step-by-Step Substitution:- m1 : m2 = 3 : 1, y1 = 5, y2 = y, yP = 2
- 2 = 3(y) + 1(5)3 + 1
- 2 = 3y + 54 ⇒ 8 = 3y + 5 ⇒ 3y = 3 ⇒ y = 1
A letter from the word INDEPENDENCE is selected at random. What is the probability that the letter selected is a vowel which occurs the maximum number of times in the given word?
P(E) = Favourable OutcomesTotal Outcomes
Step-by-Step Analysis:- Total letters in INDEPENDENCE = 12
- Frequency of vowels: ‘I’ = 1, ‘E’ = 4
- Maximum occurring vowel = ‘E’ (Count = 4)
- P(E) = 412 = 13
For the following distribution, the lower limit of the median class is:
| Class | 0-5 | 5-10 | 10-15 | 15-20 | 20-25 |
|---|---|---|---|---|---|
| Frequency | 10 | 15 | 12 | 20 | 9 |
- 0-5: f = 10, cf = 10
- 5-10: f = 15, cf = 25
- 10-15: f = 12, cf = 37
- 15-20: f = 20, cf = 57
- 20-25: f = 9, cf = 66
- N = 66 ⇒ N2 = 33
- Cumulative frequency just greater than 33 is 37 (Class 10-15).
- Lower limit of median class 10-15 = 10
The length of a tangent drawn from a point at a distance of 10 cm from the centre of the circle is 8 cm. The radius of the circle is:
Pythagoras Theorem in right-angled triangle OTP: OP2 = OT2 + PT2
Step-by-Step Substitution:- Distance from centre (OP) = 10 cm, Tangent length (PT) = 8 cm
- 102 = r2 + 82
- 100 = r2 + 64 ⇒ r2 = 36 ⇒ r = 6 cm
Mean and median of certain data are 32 and 30 respectively. Using empirical formula, the value of mode is:
Empirical Relationship: Mode = 3 × Median − 2 × Mean
Step-by-Step Substitution:- Given: Median = 30, Mean = 32
- Mode = 3(30) − 2(32) = 90 − 64 = 26
A ladder 15 m long reaches a window 12 m above the ground. The distance of the foot of the ladder from the base of the wall is:
Pythagoras Theorem: Hypotenuse2 = Perpendicular2 + Base2
Step-by-Step Substitution:- Ladder = 15 m, Height = 12 m
- 152 = 122 + Base2 ⇒ Base2 = 225 − 144 = 81 ⇒ Base = 9 m
The value of sin2 60° − 2 tan2 45° − cos2 30° is:
sin 60° = √32, tan 45° = 1, cos 30° = √32
Step-by-Step Substitution:- Expression = 34 − 2(1) − 34 = −2
The perimeter of two similar triangles is 28 cm and 35 cm respectively. If one side of the first triangle is 8 cm, then the corresponding side of the second triangle is:
Ratio of perimeters of two similar triangles = Ratio of their corresponding sides.
Step-by-Step Substitution:- 2835 = 8x ⇒ 45 = 8x ⇒ 4x = 40 ⇒ x = 10 cm
If in ΔABC and ΔPQR, ∠B = ∠Q, ∠R = ∠C and AB = 2PQ, then the two triangles are:
- By AA Similarity Criterion: Since ∠B = ∠Q and ∠C = ∠R, ΔABC ~ ΔPQR.
- Side ratio = 2 ≠ 1, so sides are unequal. Hence, they are similar but not congruent.
If tangents PA and PB from a point P to a circle with centre O are inclined to each other at an angle of 80°, then ∠AOB is equal to:
∠AOB and ∠APB are supplementary (∠AOB + ∠APB = 180°).
Step-by-Step Substitution:- ∠AOB + 80° = 180° ⇒ ∠AOB = 100°
Two cubes each of volume 64 cm3 are joined end to end to form a cuboid. The total surface area of the resulting cuboid is:
- Edge of cube a = (64)1/3 = 4 cm
- Cuboid Dimensions: l = 8 cm, b = 4 cm, h = 4 cm
- TSA = 2(8×4 + 4×4 + 4×8) = 2(32 + 16 + 32) = 160 cm2
ASSERTION (A): The probability of getting number 8 on rolling a die is zero (0).
REASON (R): The probability of an impossible event is zero (0).
ASSERTION (A): If a line divides any two sides of a triangle in the same ratio, then the line is parallel to the third side.
REASON (R): Line drawn from midpoint of one side of triangle parallel to another will bisect the third side.
SECTION B (Very Short Answers) 10 Marks
Q21 (A): Find the smallest number which when increased by 17 is exactly divisible by both 520 and 468.
- Prime factorization of 520 = 23 × 5 × 13
- Prime factorization of 468 = 22 × 32 × 13
- LCM(520, 468) = 23 × 32 × 5 × 13 = 4680
- Required number = 4680 − 17 = 4663
Q21 (B): Show that (25)n will never end with digit zero for any natural number n.
- (25)n = (52)n = 52n
- By Fundamental Theorem of Arithmetic, prime factorization is unique. Since factor 2 is missing, it cannot end with 0.
If 3 sin θ = 4 cos θ, find the value of sin θ + cos2 θ.
- tan θ = 4/3 ⇒ sin θ = 4/5, cos θ = 3/5
- sin θ + cos2 θ = 45 + (35)2 = 45 + 925 = 2925
If one zero of the quadratic polynomial 2x2 − 3x + p is 3, find the value of p. Also, find the other zero.
- p(3) = 0 ⇒ 2(3)2 − 3(3) + p = 0 ⇒ 18 − 9 + p = 0 ⇒ p = −9
- Sum of zeroes = 3 + β = 3/2 ⇒ β = −3/2
In the given figure, PA is a common tangent and QB and PC are tangents from Q and P. If QB = 5 cm and PC = 9 cm, evaluate length of PQ.
- QA = QB = 5 cm, and PA = PC = 9 cm (tangents from external point)
- PQ = PA − QA = 9 − 5 = 4 cm
Q25 (A): Points A(3, 1), B(5, 1), C(a, b) and D(4, 3) are vertices of a parallelogram ABCD. Find values of a and b.
- Midpoint AC = Midpoint BD ⇒ (3+a2, 1+b2) = (92, 2)
- 3 + a = 9 ⇒ a = 6 | 1 + b = 4 ⇒ b = 3
Q25 (B): Find a linear relation between x and y such that P(x, y) is equidistant from A(1, 4) and B(−1, 2).
- PA2 = PB2 ⇒ (x − 1)2 + (y − 4)2 = (x + 1)2 + (y − 2)2
- Simplifying gives 4x + 4y − 12 = 0 ⇒ x + y − 3 = 0
SECTION C (Short Answers) 18 Marks
Given that √5 is irrational, prove that 2 + 3√5 is irrational.
- Assume 2 + 3√5 = a/b (where a, b are co-prime integers, b ≠ 0).
- 3√5 = a − 2bb ⇒ √5 = a − 2b3b
- Since a, b are integers, RHS is rational, which means √5 is rational.
- This contradicts the fact that √5 is irrational. Hence, 2 + 3√5 is irrational.
Q27 (A): Prove that AP = 12(AB + BC + CA).
- Tangents: AP = AR, BP = BQ, CQ = CR
- Perimeter ΔABC = AB + BC + CA = AB + (BQ + QC) + CA = (AB + BP) + (CR + CA) = AP + AR = 2AP
- Hence, AP = 12(AB + BC + CA).
Q27 (B): Prove that ∠APB = 2∠OAB.
- In ΔPAB, PA = PB ⇒ ∠PAB = 90° − θ/2 (where θ = ∠APB)
- ∠OAP = 90° ⇒ ∠OAB = 90° − (90° − θ/2) = θ/2 ⇒ ∠APB = 2∠OAB.
Determine ratio in which (−6, y) divides segment joining A(−3, −1) and B(−8, 9). Also find y.
- −6 = k(−8) − 3k + 1 ⇒ −6k − 6 = −8k − 3 ⇒ 2k = 3 ⇒ k = 3/2
- y = (3/2)(9) + 1(−1)(3/2) + 1 = 25/25/2 = 5
In right ΔACB, AB = 29, BC = 21, ∠ABC = θ. Find: (i) 1 + tan2 θ, (ii) cos2 θ − sin2 θ.
- AC = √(292 − 212) = √400 = 20
- (i) 1 + tan2 θ = 1 + (20/21)2 = 841/441
- (ii) cos2 θ − sin2 θ = (21/29)2 − (20/29)2 = 41/841
Q30 (A): Mean of distribution is 48, total frequency is 50. Find missing frequencies x and y.
- Equation 1: 25 + x + y = 50 ⇒ x + y = 25
- Equation 2: Σfixi / 50 = 48 ⇒ 9x + 13y = 277
- Solving gives x = 12, y = 13
Q30 (B): Find the Modal weight of 50 students.
- Modal class = 55 − 65 (f1 = 20, f0 = 10, f2 = 12, h = 10, l = 55)
- Mode = 55 + [20 − 1040 − 22] × 10 = 55 + 5.56 = 60.56 kg
The sum of digits of a two-digit number is 9. Nine times this number is twice the reversed number. Find the number.
- x + y = 9 and 9(10x + y) = 2(10y + x) ⇒ 8x − y = 0
- Adding equations: 9x = 9 ⇒ x = 1, y = 8. Number = 18.
SECTION D (Long Answers – 5 Marks) 20 Marks
Prove that if a line is drawn parallel to one side of a triangle intersecting other two sides, then it divides the sides in the same ratio.
- Area(ΔADE)/Area(ΔBDE) = (1/2)×AD×EN(1/2)×DB×EN = AD/DB
- Area(ΔADE)/Area(ΔDEC) = (1/2)×AE×DM(1/2)×EC×DM = AE/EC
- Since ΔBDE and ΔDEC lie on same base DE and between same parallels DE || BC, Area(ΔBDE) = Area(ΔDEC).
- Therefore, AD/DB = AE/EC. Hence Proved!
Q33 (A): A train travels 360 km at uniform speed. If speed had been 5 km/h more, it would take 1 hour less. Find speed of train.
- 360/x − 360/(x + 5) = 1 ⇒ x2 + 5x − 1800 = 0
- (x − 40)(x + 45) = 0 ⇒ Speed = 40 km/h (rejecting negative speed).
Q33 (B): John and Jivanti have 45 marbles. Both lost 5 marbles each, product of remaining is 124. Find initial marbles.
- (x − 5)(40 − x) = 124 ⇒ x2 − 45x + 324 = 0
- (x − 36)(x − 9) = 0 ⇒ Initial counts were 36 and 9.
Hemisphere drilled out of wooden cube of side 21 cm. Find (i) volume of remaining wood, (ii) total surface area of solid.
- Radius r = 21/2 = 10.5 cm.
- (i) Volume = a3 − (2/3)πr3 = 9261 − 2425.5 = 6835.5 cm3
- (ii) TSA = 6a2 − πr2 + 2πr2 = 2646 + 346.5 = 2992.5 cm2
Q35 (A): Drone observes ambulance with depression angles 30° and 60° (12 minutes later). Find total time taken.
- AP1 = h√3, AP2 = h/√3 ⇒ Distance P1P2 = 2h/√3 in 12 min.
- Remaining distance AP2 takes 6 min ⇒ Total Time = 12 + 6 = 18 minutes.
Q35 (B): Statue 1.6 m tall on pedestal. Elevation to top is 60°, to bottom is 45°. Find height of pedestal.
- tan 45° = h/x ⇒ x = h; tan 60° = (h + 1.6)/h ⇒ h(√3 − 1) = 1.6
- h = 1.6/(√3 − 1) = 0.8(√3 + 1) m (≈ 2.19 m).
SECTION E (Case Study Competency Questions) 12 Marks
Hand fan sector boundary radius R = 10 cm, inner radius r = 4 cm, θ = 60°.
- (i) Area of fan: (60/360)×(22/7)×100 = 1100/21 cm2 (52.38 cm2) [1M]
- (ii) Area of black sheet: (60/360)×(22/7)×(100 − 16) = 44 cm2 [1M]
- (iii)(A) Tape length: Outer arc + Inner arc + 2(R − r) = 44/3 + 12 = 80/3 cm (26.67 cm) [2M]
- OR (iii)(B) Central angle for 29.6 cm tape: θ = 72° [2M]
Tree plantation: Trees per section = 2n + 3 (2 sections per class). Tn = 4n + 6.
- (i) Common difference: T1 = 10, T2 = 14 ⇒ d = 4 [1M]
- (ii) Trees by Class VI: 4(6) + 6 = 30 trees [1M]
- (iii)(A) Total trees (I to XII): S12 = (12/2)(10 + 54) = 384 trees [2M]
- OR (iii)(B) Class that planted 34 trees: 4n + 6 = 34 ⇒ Class VII [2M]
400 T-shirts: 312 Good, 54 Minor defects, 34 Major defects.
- (i) P(Harish buys): 312/400 = 39/50 (0.78) [1M]
- (ii) P(Trader buys): 366/400 = 183/200 (0.915) [1M]
- (iii)(A) P(Not good): 88/400 = 11/50 (0.22) [2M]
- OR (iii)(B) P(Neither buys): 34/400 = 17/200 (0.085) [2M]