Question 536591
Boat  	speed	=x	mph					
current    	speed	=y	mph					
against current x-y		6.00	hours					
With current x+y		3.00	hours					
								
Distance = same=		60	miles					
t=d/r								
60	/	(	x	-	y	)=	6.00	
6	(	x	-	y	)	=	60.00	
6	x		-6	y	=	60	....................1	
60	/	(	x	+	y	)=	3.00	
3.00	(	x	+	y	)	=	60	
3.00	x	+	3.00	y	=	60	...............2	
Multiply (1) by 	1.00							
Multiply (2) by	2.00							
we get								
6	x	+	-6	y	=	60		
6	x	+	6	y	=	120		
12	x	=	180					
/	12							
x 	=	15	mph					
								
plug value of x in (1)								
6	x		-6	y	=	60		
90			-6	y	=	60		
-6	y	=	60	-90				
-6	y	=	-30					
	y	=	5	mph				
	Boat  	15	mph					
	current    	5	mph	

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