How many families were surveyed when asked what vehicles they own 39 own cars 21 own trucks 23 own vans 12 own cars and trucks 14 own cars and vans 5 own vans and trucks and 2 own all 3 types?

How many families were surveyed when asked what vehicles they own 39 own cars 21 own trucks 23 own vans 12 own cars and trucks 14 own cars and vans 5 own vans and trucks and 2 own all 3 types?
50