Question
A rectangular piece of copper foil of length 21 cm and
area 1386 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 = 1386/21 = 66 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 = 66 Radius of cylinder = 66 ÷ (2 × 22/7) = (66/44) × 7 = 10.5 cm So, volume of the cylinder so formed = π × (radius)2 × height = (22/7) × 10.5 × 10.5 × 21 = 7276.5 cm³
128, 132, 123, 139, 113, 150
Find the wrong number in the following series.
638, 518, 451, 352, 297, 218
Find the wrong number in the given number series.
16, 24, 36, 54, 81, 120.5
Find the wrong number in the given number series.
13, 20, 31, 44, 62, 80
21Â Â Â Â Â Â Â Â Â Â 32Â Â Â Â Â Â Â Â Â Â 54Â Â Â Â Â Â Â Â Â Â 86Â Â Â Â Â Â Â Â Â Â 131Â Â Â Â Â Â Â Â 186
...1080, 1058, 1016, 934, 772, 440
547, 594, 640, 691, 741, 792
- Find the wrong number in the given number series.
27, 38, 52, 70, 94, 122 Find the wrong number in given series.
918, 943, 992, 1073, 1194, 1388
In each of the following number series, one term is wrong. Find the wrong term.
2, 9, 28, 65, 128, 217, 344
