Question 583416
forward speed = x  kph
return speed = x+150 kph

distance = 8500 km

return time less by 2 hours

time forward - time return = 2

t=d/r
8500/x-8500/(x+150)= 2

LCD = x(x+150)
multiply by LCD
8500(x+150) -8500x = 2x(x+150)
8500x+1275000-8500x=2x^2+300x

2x^2+300x-1275000=0
/2
x^2+150x-637500=0

Find the roots of the equation by quadratic formula								
								
a=	1	,	b=	150	,	c=	-637500	
								
b^2-4ac=	22500	+	2550000					
b^2-4ac=	2572500		
{{{	sqrt(	2572500	)=	1603.9	}}}
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}								
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}								
x1=(	-150	+	1603.9	)/	2			
x1=	726.95							
x2=(	-150	-1603.9	) /	2				
x2=	-876.95							
Ignore negative value								
Plane  	speed	726.95	mph	

time to camp = 8500/727= 11.69 hours

return time was 8500/877= 9.69 hours