A family wants to cross a boat that holds no more than 250 lbs the husband weighs 160 lbs his wife weighs 130 lbs the daughter weighs 85 lbs and the son weighs 115 lbs how can they all get across?

cross the boat or cross a body of water on a boat?

I figure...
The fewest number of trips It can take is 3.

Mother and son across (245 lbs)
son comes back
brother and sister across (200 lbs)
sister goes back
father and daughter across. (245 lbs)