In the context of a feasibility study describe one cost, benefit and any social effects?

This is for my homework, my teacher won't help me and none of my friends understand it either!

A feasibility study looks at the positive and negative sides to a proposal. For example, suppose your school's has twice as many students as it was designed for and someone proposes to build a new building. Costs would be buying the land, building the building, furnishing it, and paying more teachers. The benefit would be that students would get a better education due to there being only half as many in the classroom. The social effects would be that friends would be separated, a new rivalry would begin between the schools, some students would have to travel farther to school, some would be closer and Facebook wouldn't work on the new school computers either. :-)