A train covers the first 5 km of its journey at a speed of 30 km/hr and the next 15 km at a speed of 45 km/hr. What is the average speed of the train ?

What is the equation of the ellipse having foci (±2, 0) and the eccentricity 1/2?

What is the ratio in which the point C(2, 20/7) divides the line joining the…

What is the equation of the circle which passes through the points (3, -2) and…

The two circles x² + y² = r² and x² + y² – 10x +…

If the three consecutive vertices of a parallelogram are (-2, -1), (1, 0) and (4,…