structues help

if anyone has problems with the calculations of structures 4.. well you are not the only one.. it seems like the span of the building that was given when we calculate the beams and slabe it comes to 1000 which is just imposibble to have a beam of 500 and slab of 500 for a double storey house.. really is rediculous either i did it completly wrong or .. he exaplained it not so well.. please help anyone!!!try figure this thing out.. but iam glad that we do have an exstension for the project the only problem is that it will intafeer with other handins and portfolios.. xoxo