Given :
You drive 200 miles in 3 hours before stopping for lunch and gas. After lunch you travel 250 miles in an hour and a half.
To Find :
Average speed.
Solution :
We know, average speed is given by :
[tex]v=\dfrac{\text{Total distance covered}}{\text{Total time taken}}\\\\v=\dfrac{200+250}{3+1.5}\ miles/hr\\\\v=\dfrac{450}{4.5}\ miles/hr\\\\v=100\ miles/hr[/tex]
Therefore, average speed of the journey is 100 miles/hr.
Hence, this is the required solution.