Question
A rectangular piece of copper foil of length 28 cm and
area 1232 cm2 is folded along its width to form a cylinder such that there is only one layer of copper foil on any part of the cylinder. What is the volume (in cm3) of the cylinder so formed?Solution
Width of the rectangular piece of copper foil = 1232/28 = 44 cm Since the foil is folded along its width to form a cylinder without any double layer, circumference of the cylinder formed = width of the rectangular foil Also, height of the cylinder so formed = length of the rectangular copper foil So, 2 × π × radius = 44 Radius of cylinder = 44 ÷ (2 × 22/7) = (44/44) × 7 = 7 cm So, volume of the cylinder so formed = π × (radius)2 × height = (22/7) × 7 × 7 × 28 = 4312 cm³
The volume of a cube is 64 cm³. If the cost of painting the cube is Rs. 15 per cm², then find the cost of painting five faces of the cube.
The circumference of a circle is 44 cm and the length of the rectangle is 4 times the radius of the circle. Find the area (in cm2) of the rec...
The average weight of five friends A, B, C, D and E is (x+8) years while the average weight of C and E is (x-8) kg. If the weight of another person F is...
A figure is formed by revolving a rectangular sheet of dimensions 7cm ×4cm about its length. What is the volume of the figure. thus formed. (in c...
A barrel has 140 liters of mixture of alcohol and water, in which water is 10%. 30 litre of this mixture was taken out and replaced with “X”...
A square is converted into a rectangle by increasing its length by 30 % and decreasing its width by 10%. Which of the following statements is true?
- 'A hall has a floor covered with rectangular tiles, each measuring 90 cm by 50 cm. The hall’s dimensions are 720 cm in length and 3 meters in width. Find...
The ratio between the length and the breadth of a rectangular park is 3 : 2. If a man cycling along the boundary of the park at the speed of 12 km/hour...
Due to economic surge the price of eggs suddenly reduced by 40%. This enabled a woman to buy 64 more for $30. Then the reduced price per dozen is :
Find the surface area of the smallest cube that can perfectly fit a sphere of volume 47916π cm3 inside it.
Relevant for Exams:
