An apartment complex currently houses 280 people who are spread out across 4 buildings standing on 200,000 square feet of land. the owner of the complex is planning to expand by purchasing an additional square plot of land measuring 200 ft by 200 ft and constructing one more apartment building on this plot.

200 000/280 = 714 square feet per person in 4 buildings 
 

200 * 200 = 40000 square feet+ 200 000 = 240 000 square feet in 5 buildings 

280=200000 
1person = x 
280x= 200000 
x= 200000/280= 143 square feet per person( rounded) in 4 buildings 
 

200 000 = 143 
240000= x 
200000x= 34320000 
x= 34320000/200000= 172 square feet per person ( rounded)in 5 buildings 
 

172-143= 29.6 = 30 foot difference/loss of footage per person with 5 buildings 

So B is the answer.