A rectangular parking lot is 25 ft. ny 50 ft is increased on all 4 sides by the same amount. The area increased by 400 sq ft. What are the new dimensions of the parking lot?

Answer 1

(25+L)(50+L)=25*50+400

25*50+75L+L^2=25*50+400

L^2+75L-400=0

l=(-75+-sqrt(75^2+1600))/2=(-75+-85)/2=
= 5

new dimensions: 30*55