Thirty-six vehicles are parked in a parking lot in a single row. After the first car, there is one scooter. After the second car, there are two scooters. After the third car, there are three scooters and so on. Work out the number of scooters in the second half row.

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.