A pipe of diameter d can drain a certain water tank in 40 minutes. The time taken by a pipe of diameter 2d for doing the same job in: 

The total surface area of a hemisphere is 166.23 sq cm, find its radius?

If the volume of two cubes are in the ratio of 343: 512, then what is the ratio of their total surface area?

If the radius and height of a cylinder increase by 20% and15% respectively. Then what is the % change in curved surface area? 

The perimeter of a triangle is equal to perimeter of a rectangle. Length of rectangle is 75% of side of a square and ratio of length to breadth of rectangle is 3 : 2. If difference between perimeter of square and that of rectangle is 36 cm, then find perimeter of triangle?

The area of a circle, is 3850 sq.m. What will be its circumference?

The length, width and height of a room are 10 meters, 8 meters and 6 meters respectively. What will be the largest bamboo length that can be kept in this room?