Question 633335
Boat  	speed	=x	mph						
current     	speed	=y	mph						
againstcurrent x-y		3	hours						
with current x+y		2	hours						
									
Distance = 		12	miles		distance=		12		
t=d/r	against	current     							
12.00	/	(	x	-	y	)=	3.00		
									
3.00	x	-	-3.00	y	=	12.00	....................1	
downstream									
12.00	/	(	x	+	y	)=	2.00		
2.00	(	x	+	y	)	=	12.00		
2.00	x	+	2.00	y	=	12.00	...............2		
Multiply (1) by	2.00								
Multiply (2) by	3.00								
we get									
6.00	x	+	-6.00	y	=	24.00			
6.00	x	+	6.00	y	=	36.00			
12.00	x	=	60.00						
/	12.00								
x	=	5	mph						
									
plug value of x in (1)									
3	x		-3	y	=	12			
15			-3	y	=	12			
-3	y	=	12	-15					
-3	y	=	-3						
	y	=	1	mph					
	Boat  	5	mph						
	current     	1	mph