Question 541135
plane speed	x	mph										
wind speed	50	mph										
												
Distance with wind	1200	miles										
Distance against wind	1000	miles										
												
speed with wind	x	+	50	mph								
speed against	x		-50	mph								
Total   time =		4	hours									
Time with current=		1200	/(	x	+	50	)					
time against current 		1000	/	(	x	-50	)					
												
Time with  current + time against  =			4	hours								
												
1200/(	x+50)+1000/(x-50)=4
LCD =(x+50)*(x-50)				
multiply the equation by the LCD												
we get												
1200*(x	-50)+1000(x+50)=4
1200x-60000+1000x+50000	=4x^2	
2200x-10000=4x^2-10000					
4x^2-2200x+10000-10000	=	0				
4x^2-2200x=	0						
/	4											
X^2-550	x=0	
x^2=550x
x=550 mph

m.ananth@hotmail.ca