Total number of 6-digit numbers in which only and all the five digits 1, 3, 5, 7 and 9 appear, is :

If y = mx + 4 is a tangent to both the parabolas, y² = 4x and x² = 2by, then b is equal to :

The area of the region, enclosed by the circle x² + y² = 2 which is not common to the region bounded by the parabola y² = x and the straight line y = x, is:

If the distance between the foci of an ellipse is 6 and the distance between its directrices is 12, then the length of its latus rectum is :