A car travels a constant speed of 60 m/hr in a straight line, then continues in the same direction at constant speed x. The average speed for the entire trip is 30 m/hr. What is the speed of x?

The time to cover the first part is given by:

\frac{D_1}{60}

The time to cover the second part is given by:

\frac{D_2}{x}

The average speed is given by:

Average\ speed = \frac{D_1 + D_2}{\frac{D_1}{60} + \frac{D_2}{x}} = 30

Well, there is not enough information, or I'm too tired to see what I'm missing...