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Home ‣ Aptitude ‣ Volume and Surface Area Comments
- Question
- A cylindrical vessel of radius 4 cm contains water. A solid sphere of radius 3 cm lowered into the water until it is completely immersed. The water level in the vessel will rise by?
Options- A. 4/9 cm
- B. 9/4 cm
- C. 2/3 cm
- D. 4/5 cm
- Correct Answer
- 9/4 cm
ExplanationVolume of the sphere = Volume of the water displaced
Let the required height to which the water rises be h.
Then, ?r12h = 4/3 ?r23
? 16 h = 4/3 x 27 ? h = 36/16 = 9/4 cm - 1. A cylindrical tub of radius 12 cm contains water to a depth of 20 cm. A spherical iron ball is dropped into the tub and thus the level of water is raised by 6.75 cm. What is the radius of the ball?
Options- A. 6 cm
- B. 9 cm
- C. 8 cm
- D. None of these Discuss
- 2. If the height of the right circular cone is increased by 200% and the radius of the base is reduced by 50%. Then, the change in the volume of cone is?
Options- A. increase by 25%
- B. increase by 50%
- C. remains unchanged
- D. decreases by 25% Discuss
- 3. If each side of a cube is decreased by 19 %, then decrease in surface area of cube is?
Options- A. 40.4%
- B. 38.4%
- C. 35.6%
- D. 34.39% Discuss
- 4. If radius of sphere is decreased by 24%. By what per cent does the surface area decrease?
Options- A. 44%
- B. 49%
- C. 42.24%
- D. 46.2% Discuss
- 5. The base radius and height of a cone are doubled. The ratio of the new volume to original volume is?
Options- A. 8 : 7
- B. 8 : 3
- C. 8 : 1
- D. 8 : 5 Discuss
- 6. A wooden box (open at the top) of thickness 0.5 cm, length 21 cm, width 11 cm and height 6 cm is painted on the inside. The expenses of painting are ? 70. What is the rate of painting per square centimetre?
Options- A. ? 0.7 per cm2
- B. ? 0.5 per cm2
- C. ? 0.1 per cm2
- D. ? 0.2 per cm2 Discuss
- 7. A wooden box of dimensions 8 m x 7 m x 6 m is to carry rectangular boxes of dimensions 8 cm x 7 cm x 6 cm. The maximum number of boxes that can be carried in 1 wooden box is?
Options- A. 1200000
- B. 1000000
- C. 9800000
- D. 7500000 Discuss
- 8. If the length breadth and the height of cuboid are in the ratio 6 :5 : 4 and if the total surface area is 33300 cm 2, then the length, breadth and height in cm. are respectively?
Options- A. 90, 85, 60
- B. 85, 75, 60
- C. 90, 75, 70
- D. 90, 75, 60 Discuss
- 9. If the length of diagonal of a cube is 8? 3 cm, then its surface area is?
Options- A. 512 cm2
- B. 384 cm2
- C. 192 cm2
- D. 786 cm2 Discuss
- 10. The length of longer pole that can be placed on the floor of a room is 10 m and the length of the longest pole that can be placed in the room is 10? 2m. The height of the room is?
Options- A. 6 m
- B. 7.5 m
- C. 8 m
- D. 10 m Discuss
Volume and Surface Area problems
Search Results
Correct Answer: 9 cm
Explanation:
Volume of the spherical ball = Volume of the water displaced
? 4/3 ?r3 = ?(12)2 x 6.75
? r3 = 144 x 6.75 x 3/4 = 729
? r = 9 cm
Correct Answer: decreases by 25%
Explanation:
From the formula the net change in volume is given as [x + y + z + (xy + yz + zx)/100 + xyz/(100)2 ] %
Here, x = 200, y = z = -50 (-ve sign for decrease)
= [ 200 + (-50) + (-50) + (200) x (-50) + (-50) x (-50) + (-50) x (200)/100 + (200) x (-50) x (-50)/(100)2 ] %
= 100 + (-10000 + 2500 - 10000)/100 + 500000/100 x 100 ] %
= [ 100 + (-17500)/100 + 50]%
= (150 - 175)% = -25% (-ve sign implies for a decrease )
So, the volume is decreased by 25%.
Correct Answer: 34.39%
Explanation:
The net decrease in the surface area of the cube is given by
[x + y + xy/100] %
Here, x = y = 19%
= [-19 + (-19) + (-19) x (-19)/100] %
= [-38 + 361/100] %
= [-38 + 3.61] %= -34.39% (-ve sign implies for decrease)
Correct Answer: 42.24%
Explanation:
The decrease in volume is given [ x + y + xy/100 ] %
Here , x = y = -24
= [(-24) + (-24) + (-24) x (-24)/100] %
= [-48 + 576/100] % = -48 + 5.76 = - 42.24 %
(-ve sign denotes decrease in volume)
Correct Answer: 8 : 1
Explanation:
Let original radius = r and height = h
Original volume = (1/3)?r2h
New radius = 2r and new height = 2h
? New volume = 1/3 x ?(2r)2 x 2h = 8/3?r2h
Required ratio = 8/3?r2h : 1/3?r2h = 8 : 1
Correct Answer: ? 0.1 per cm2
Explanation:
As the box is painted from inside, the dimensions of the box from inside are
Length = (21 - 05 - 05) = 20 cm
Breadth = (11 - 05 - 05) = 10 cm and height = (6 - 05) = 5.5
Total number of faced to be painted = 4 walls + One base
The dimensions of two of the walls = 2 x (10 x 5.5)
The dimensions of the remaining two = 2 x (20 x 5.5) and that of the base = (20 x 10 ) and so the total area to be pained = 2 x (10 x 5.5) + 2 x (20 x 5.5) + (20 x 10 ) = 530cm3
Since, the total expenses of painting this area is ?70, the rate of painting
= 70/530 = 0.13 = ? 0.1 per cm3 (approx)
Correct Answer: 1000000
Explanation:
Number of boxes = (Volumes of wooden box in cm3) / (Volume of 1 small box)
= (800 x 700 x 600) / (8 x 7 x 6) = 1000000
Correct Answer: 90, 75, 60
Explanation:
Let length = 6k, breadth = 5k and height = 4k in cm
? 2(6k x 5k + 5k x 4k + 6k x 4k) = 33300
? 148k2 = 33300
? k2 = 33300/148 = 225
? k = 15
? Length = 90 cm, Breadth = 75 cm, Height = 60 cm
Correct Answer: 384 cm2
Explanation:
? ?3a = 8?3
? a = 8
? Surface area = 6a2
= (6 x 8 x 8) cm2
= 384 cm2
Correct Answer: 10 m
Explanation:
? l2 + b2 = (10)2 = 100
And l2 + b2 + h2 = (10?300)2 = 200
? h2 = (200 - 100) = 100
? h = 10 m
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