Distance covered to travel house and school, d1 = 1.22 miles.
Distance covered in 3 laps, d2 = 3 × 0.25 = 0.75 miles.
Distance between halfway to the gas station from school,
d3 = 2.68÷2 = 1.34 miles.
Distance from his last position to home, d4 = 0.49 miles.
So, total distance covered is :

Therefore, total distance covered is David is 3.8 miles.
Hence, this is the required solution.