Mensuration Questions

Multiple choice
  1. 8 : 1

  2. 2 : 1

  3. 1 : 2

  4. 1 : 8

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Volume of cone V = (1/3)πr²h. For first cone: V₁ = (1/3)πr²h. For second cone (height doubled, radius same): V₂ = (1/3)πr²(2h) = 2V₁. The ratio V₁:V₂ = 1:2. This tests understanding that volume is directly proportional to height when radius is constant, since V ∝ h.

Multiple choice
  1. Only I

  2. Only II

  3. Both together are sufficient

  4. Both together are not sufficient

  5. Any one is sufficient

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

From Statement I: Curved Surface Area (CSA) = 2πrh = 396, and Total Surface Area (TSA) = 2πr(r+h) = 1628. Since TSA = CSA + 2πr², we get 1628 = 396 + 2πr², giving 2πr² = 1232. This allows finding r. With r known, CSA = 2πrh = 396 gives h = 396/(2πr). Statement I alone is sufficient. Statement II relates r and h but gives no numerical values, making it insufficient alone. Option A is correct.

Multiple choice
  1. 680 sq. cm

  2. 800 sq. cm

  3. 770 sq. cm

  4. 720 sq. cm

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total length = cylinder height + 2 × radius = 35 cm. Given diameter = height/4, so 2r = h/4, meaning h = 8r. Therefore: 8r + 2r = 35, so 10r = 35 and r = 3.5 cm. Height h = 28 cm. Surface area = curved surface of cylinder + surface of sphere = 2πrh + 4πr² = 2π × 3.5 × 28 + 4π × 3.5² = 196π + 49π = 245π ≈ 770 sq. cm.

Multiple choice
  1. 2.25 cm.

  2. 2.5 cm.

  3. 2.75 cm.

  4. 3.25 cm.

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Volume of cube with side 11 cm = 11³ = 1331 cm³. Volume of cylinder = πr²h = πr² × 56. Equating: πr² × 56 = 1331. Solving: r² = 1331/(56π) ≈ 1331/175.93 ≈ 7.56. Therefore: r ≈ √7.56 ≈ 2.75 cm.

Multiple choice
  1. 5:9

  2. 3:7

  3. 5:4

  4. 16:9

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given r:h = 4:3, the slant height l forms a 3-4-5 triangle, so l = 5. CSA = πrl = πr(5), TSA = πr(r+l) = πr(4+5) = 9πr. Ratio CSA:TSA = 5πr:9πr = 5:9.

Multiple choice
  1. 616 cm2/सेमी2

  2. 462 cm2/सेमी2

  3. 154 cm2/सेमी2

  4. 654 cm2/सेमी2

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Area between circles = π(R² - r²) where R = 14, r = 7. Area = π(14² - 7²) = π(196 - 49) = π(147). Using π = 22/7: Area = (22/7) × 147 = 22 × 21 = 462 cm².

Multiple choice
  1. 1 m.

  2. 2 m.

  3. 2.5 m.

  4. 0.5 m.

  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Room area is 100 sq m, so side length is 10 m. Let carpet side = x. Then carpet area = x² and oil cloth area = 100 - x². The cost equation: 18x² + 7.5(100 - x²) = 1422. Solving: 10.5x² = 672, so x² = 64 and x = 8 m. The oil cloth borders the carpet on all sides, so its width = (10 - 8)/2 = 1 m. Option A is correct.

Multiple choice
  1. I and II

  2. I and III

  3. Only III

  4. I and either II or III

  5. Any two of the three

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement I gives the ratio but not actual dimensions. Statement II gives length via square area and painting rate. Statement III gives breadth via triangle area and repeats painting rate. We need I plus either II or III to get all dimensions and cost information.

Multiple choice
  1. Only II

  2. All I, II and III

  3. Only I and II

  4. Only II and III

  5. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

To find the painting cost, we need the total wall area minus door/window area. Wall area = 2 × length × height + 2 × width × height = 2(16×12) + 2(15×12) = 384 + 360 = 744 m². Paintable area = 744 - 60 = 684 m². Cost = 684 × 5.50 = Rs. 3762. All three statements I, II, and III are necessary - length and width to calculate perimeter, height for wall dimensions, and door/window area for deductions.

Multiple choice
  1. Only A and B

  2. Only B

  3. Only C

  4. Either A or C

  5. Data inadequate

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Painting cost requires cost per unit area. A gives only floor area. B gives ratios but no dimensions. C gives wall area but not which wall. Even combining all, we don't know cost per square meter or which two adjacent walls to paint. Data is inadequate.

Multiple choice
  1. Quantity I > Quantity II

  2. Quantity I ≥ Quantity II

  3. Quantity II > Quantity I

  4. Quantity II ≥ Quantity I

  5. Quantity I = Quantity II or Relation cannot be established

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Quantity I: Rectangle sides in ratio 3:1. Let sides be 3x and x. Perimeter = 2(3x + x) = 8x. Semi-circle with area 77 = (1/2)πr² gives r² = 49/π, r = 7/√π. Circumference = πr + 2r = π(7/√π) + 2(7/√π) = 7√π + 14/√π. Perimeter of rectangle = twice this = 14√π + 28/√π. So 8x = 14√π + 28/√π. Area = 3x² = 3[(14√π + 28/√π)/8]². This is complex. Let me recalculate: semi-circle area 77 means (πr²)/2 = 77, so r² = 154/π ≈ 49, so r ≈ 7. Semi-circle circumference (including diameter) = πr + 2r ≈ 7π + 14 ≈ 36. Rectangle perimeter = 2 × 36 = 72. So 8x = 72, x = 9. Rectangle area = 3x × x = 3 × 81 = 243. Quantity II: Square with area 49 has side 7. Cylinder height = 7, radius = 12. CSA = 2π × 12 × 7 = 168π ≈ 528. Since 528 > 243, Quantity II is greater.

Multiple choice
  1. 25:4

  2. 50:9

  3. 27:8

  4. 51:25

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Original volume of cone = (1/3)πR²H. After 40% decrease, new radius = 0.6R. After 50% decrease, new height = 0.5H. New volume = (1/3)π(0.6R)²(0.5H) = (1/3)π(0.18R²H). Therefore ratio original:new = 1:0.18 = 50:9. The calculation correctly applies the percentage decreases to both dimensions.

Multiple choice
  1. 2.8 cm.

  2. 2.4 cm.

  3. 3.2 cm.

  4. 4.8 cm.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a shape is recast, its volume remains constant. Volume of hollow cylinder = π(R² - r²)h = π(4.3² - 1.1²) × 3 = π(18.49 - 1.21) × 3 = π × 17.28 × 3. Volume of solid cylinder = πR² × 9. Equating: πR² × 9 = π × 51.84, giving R² = 5.76, so R = 2.4 cm.

Multiple choice
  1. 22 m.

  2. 20 m.

  3. 18 m.

  4. 34 m.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cylinder curved surface area = 2πrh = 1000 cm². Wire diameter = 5mm = 0.5cm, so circumference of each turn = πd = 0.5π cm. Length of wire = CSA / wire diameter = 1000 / 0.5 = 2000 cm = 20m. The wire winds around the cylinder with its diameter as the effective spacing. Option A (22m), C (18m), and D (34m) are incorrect calculations.

Multiple choice
  1. Quantity I > Quantity II

  2. Quantity I ≥ Quantity II

  3. Quantity II > Quantity I

  4. Quantity II ≥ Quantity I

  5. Quantity I = Quantity II or Relation cannot be established

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Quantity I: The hemisphere radius is 4 cm, so its minimum bounding box must have dimensions at least 8 cm x 8 cm x 4 cm (diameter x diameter x height). With consecutive odd dimensions, the smallest such box is 7 x 9 x 11 or 9 x 11 x 13. Testing 9x11x13: volume = 1287 cm³, which is > 960 cm³. Therefore Quantity I > Quantity II.