Mathematical Ab...

A circle with center (4, −5) is tangent to the y -axis in the standard (x,y) coordinate plane. What is the radius of this circle?

The median of the set {x + 1, x + 2, x + 3, x + 4, x + 5, x + 6}, is:

A train running at a speed of 72 km/hr takes 25 seconds to cross an electric pole. What is the length of the train?

3 bells ring together at 7 AM. First bell rings after every 1 hour, second bell rings after every 2 hours and third bell rings after every 4 hours. At what time will they ring together?

In the expansion of (1 + ax)ⁿ, the first three terms are respectively 1,12x and 64x². What is n equal to:

The mean of 8 observations is 25. The 7 observations are 30, 24, 27, 22, 18, 26, 32. What is the 8th observation?

A rectangular plot is 122 m long and 88 m wide. It has a path 2 m wide all around it on the outside. Find the cost of constructing it at Rs. 2 per square meter.

A set containing n elements, has exactly ___________ subsets.