Question 715505
Tie going - time returning = 1 hours

let speed be x km/h

time = d/r
d=120

time going = 120/x

time returning = 120/(x+6)

{{{120/x - 120/(x+6) = 1}}}

multiply the equation by x(x+1)

120(x+1) -120x= x(x+1)

120x+120-120x=x^2+x

x^2+x-120=0

Find the roots of the equation by quadratic formula							
							
a=	1	b=	1	c=	-120		
							
b^2-4ac=	1	-	-480				
b^2-4ac=	481			{{{sqrt(	481	)}}}=	21.93
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}							
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}							
x1=(	-1	+	21.93	)/	2		
x1=	10.47						
x2=(	-1	-21.93	) /	2			
x2=	-11.47						
Ignore negative value			km/h				
x	=	10.47	(going speed)

add 6 for returning speed				



width =x
length = x+3

Area = L * W

Area = x(x+3) = 12

x^2+3x=12
x^2+3x-12=0

solve for x

(x+4)(x-3)=0
x= 3 which is positive

the dimensions are 4 ft by 3 ft