Question
The amount of concrete required to build a concrete
cylindrical pillar whose base has a perimeter 8.8 metre and curved surface area 17.6 sq. metre, is (Take π = 22/7)Solution
Concrete required to build pillar = Volume of the cylindrical pillar The curved surface area of a cylinder = 2πrh The base of a cylinder is a circle whose perimeter = 2πr The perimeter of the base of the pillar = 8.8 m ⇒ 2πr = 8.8 ⇒ r = 1.4 m Also, Curved surface area = 17.6 m ⇒ 2πrh = 17.6 ⇒ h = 17.6/2πr ⇒ h = 2 m Now, Volume of cylindrical pillar = πr2h ⇒ πr2h = (22/7)(1.4)2 × 2 ⇒ 308/25 = 12.32 m3 ∴ Concrete required to build the pillar is 12.32 m3
2600, 3000, 1759, 1275, 746, 170
139, 152, 172, 205, 249, 304
- Find the wrong number in the given number series.
2, 27, 252, 877, 2102, 4127 11Â Â Â Â 110Â Â Â Â Â 978Â Â Â Â 6824Â Â Â Â 34103Â Â Â Â 102290
1 Â Â Â Â Â Â 3 Â Â Â Â Â Â 7 Â Â Â Â Â Â Â 15 Â Â Â Â Â Â Â 33
...2, 6, 44, 462, 6930, 131670
125, 142, 199, 320, 489, 778
3Â Â Â Â Â Â Â Â Â 6Â Â Â Â Â Â Â Â Â 18Â Â Â Â Â 149Â Â Â Â Â Â Â Â 602Â Â Â Â Â Â Â Â 15057
...5000, 4500, 3600, 2480, 1512, 756Â Â Â
Find the wrong no in the given number series.
11, 18, 32, 60, 112, 228
