Question 638571
Plane  	speed	x	mph				
wind   	speed	15	mph				
..							
against	wind   	x	-	15	mph		
with	wind   	x   	+	15	mph		
							
Distance against	wind   	720					
Distance with	wind   	900					
Time = same	equate the time against with time with current						
t=d/r							
720	/(x-	15	)=	900	/(x+	15	)
720	*(x+	15	)=	900	*(x-	15	)
720	x  	+	10800	=	900	x	-13500
720	x  	-900	x   	=	-13500	+	-10800
-180	x  	=	-24300				
/	-180						
	x=	135	mph				
m.ananth@hotmail.ca