681 person divided into 12 vans and 9 busses

Answer 1

each van has V person capacity.

each bus has B person capacity

12V + 9B = 681

4V + 3B = 227

usually this type of problem has some additional information, but odds are vans' capacity is less than buses

so

possibilites range about

34 per van & 53 per bus

31 per van & 55 per bus

or

34 + or - 3n & 53 + or - 2 where n= any integer, but limited by V<B