Answer
There would be a surplus of 5000 apartments.
10000 apartments would be rented.
Work Step by Step
At the price of 2500, referring to the table given, the apartments supplied exceeds the apartments demanded by 15000-10000=5000, and hence there is a surplus.
Although there is 15000 apartments supplied, only 10000 apartments are demanded, hence, only 10000 apartments are rented.