Solution: Number of Scooters in Second Half of Row

Total vehicles = 36. Let number of cars = \(n\), scooters = \(\frac{n(n+1)}{2}\).
Solve \(n + \frac{n(n+1)}{2} = 36\) gives \(n=7\) cars and 28 scooters (total 35 vehicles).
Since total is 36, assume 1 extra scooter added somewhere.

The vehicle sequence (cars + scooters) goes as:
Car1, 1 scooter; Car2, 2 scooters; ... Car7, 7 scooters.

Half of 36 = 18 vehicles (second half is last 18).
Positions 19 to 36 in the sequence contain:
- Last 3 scooters of the 5th group (positions 18-20)
- All 6 scooters of the 6th group (positions 22-27)
- All 7 scooters of the 7th group (positions 29-35)

Counting scooters in these positions:
\(2 + 6 + 7 = 15\) scooters in the second half.

Final answer: 15 scooters.