Question 904345
boat   	speed	=x	mph					
current     	speed	=y	mph					
against  	current     	0.5	hours					
with	current     	0.25	hours					
								
Distance against 		4	miles	distance with 		4	miles	
t=d/r	against	current     		-				
4.00	/	(	x	-	y	)=	0.50	
0.50	(	x	-	y	)	=	0.25	
0.50	x	-	0.50	y	=	4.00	....................1	
								
4.00	/	(	x	+	y	)=	0.25	
0.25	(	x	+	y	)	=	4.00	
0.25	x	+	0.25	y	=	4.00	...............2	
Multiply (1) by	0.25							
Multiply (2) by	0.50							
we get								
0.13	x	+	-0.13	y	=	1.00		
0.13	x	+	0.13	y	=	2.00		
0.25	x	=	3.00					
/	0.25							
x	=	12.00	mph					
								
plug value of x in (1)				y				
0.50	x		-0.50	y	=	4.00		
6.00			-0.50	-6.00	=	4.00		
-0.50	y	=	4.00					
-0.50	y	=	-2.00	mph				
	y	=	4.00					
boat   	speed	12.00	mph					
current     	speed	4.00	mph					
								
m.ananth@hotmail.ca