A car is moving collinearly with a laser beam emitted by a transceiver. A laser pulse emitted at \( t = 0 \) s is received back by the transceiver 100 ns (nanoseconds) later after reflection from the car. A second pulse emitted at \( t = 0.1 \) s is received back 90 ns later. Given the speed of light is \( 3 \times 10^8 \) m/s, the average speed of the car in this interval is _________