If one van can carry 6 people, to determine how many vans are needed to carry 250 people, we divide the total number of people by the capacity of each van.

250 people ÷ 6 people per van = 41.67 vans

Since we cannot have a fraction of a van, we need to round up to the nearest whole number. Therefore, 42 vans would be needed to carry 250 people.