Francisco E. answered 05/13/14
Tutor
5
(1)
Francisco; Civil Engineering, Math., Science, Spanish, Computers.
A*B = Area= 20
2A + 2B = 18
A= 20/B, replacing in equation 2
40/B + 2B = 18B
2B^2 -18B +40 = 0
solving the quadratic we obtain B1 = 5 miles; B2 4 Miles. Then also replacing in equation 1 we get: A1 = 4 Miles and A2= 5 miles.
Answer is Length 5 miles width 4 miles. or Length 4 miles and width 5 miles.