(5.5)³-(4.5)³ is equal to : 

$$3\sqrt{ {72.9\over0.4096}}$$ is equal to : 

1008 divided by which single-digit number gives a perfect square?

The total surface area of a cube is 864 square cm. What is his volume?

The volume of a sphere and an elliptical cylinder are the same. The radius of the sphere and cylinder are 21 cm and 14 cm respectively. What is the height of the cylinder?

The price of 6 pencils is Rs. 30 and that of 12 pens is Rs. 120. What is the average price of 50 pencils and 50 pens?

A man sets out on a journey. He traveled for a total of 16 hours. He covered the first half of the distance at a speed of 40 km per hour and the second half at a speed of 60 km per hour. How much distance did he cover?

If   0.8 : X :: 5 : 8, then the value of X is