Question 841617
The area of the pool only (ignore the deck) is 15*25 = 375 square feet.


If you add on the deck, then you have to add on 5 ft to each side so you're really adding on 2*5 = 10 ft to each dimension to 15+10 = 25 by 25+10 = 35 


The dimensions of the pool+deck is 25 by 35


The area of this pool+deck combo is 25*35 = 875 square feet


Subtract the area of the pool only from the pool+deck combo to get


875 - 375 = 500


So the area of just the deck is <font color="red">500 square feet</font>