Question 584673
Boat  	speed	=x	mph					
current     	speed	=y	mph					
against wind x-y		5	hours					
with wind x+y		3	hours					
								
Distance = same=	upstream=	60	miles	Downstream = 		60	miles	
t=d/r	against	current     						
60	/	(	x	-	y	)=	5	
5	(	x	-	y	)	=	60	
5	x	-	5	y	=	60	....................1	
								
60	/	(	x	+	y	)=	3	
3	(	x	+	y	)	=	60	
3	x	+	3	y	=	60	...............2	
Multiply (1) by	3							
Multiply (2) by	5							
we get								
15	x	+	-15	y	=	180		
15	x	+	15	y	=	300		
30	x	=	480					
/	30							
x	=	16	mph					
								
plug value of x in (1)								
5	x		-5	y	=	60		
80			-5	y	=	60		
-5	y	=	60	-80				
-5	y	=	-20					
	y	=	4	mph				
	Boat  	16	mph					
	current     	4	mph