Question 805026
swimming	speed	=x	mph						
current     	speed	=y	mph						
against 	current     	0.75	hours						
with 	current     	0.5	hours						
									
Distance with	current     	15	miles		distance against	current     	15		
t=d/r	against	current     	(x-y)						
15.00	/	(	x	-	y	)=	0.75		
									
0.75	x	-	-0.75	y	=	15.00	....................1		
with	current     	(x+y)							
15.00	/	(	x	+	y	)=	0.50		
0.50	(	x	+	y	)	=	15.00		
0.50	x	+	0.50	y	=	15.00	...............2		
Multiply (1) by	0.50								
Multiply (2) by	0.75								
we get	2.00								
0.38	x	+	-0.38	y	=	7.50			
0.38	x	+	0.38	y	=	11.25			
0.75	x	=	18.75						
/	0.75								
x	=	25	mph						
									
plug value of x in (1)				y					
0.75	x		-0.75	y	=	15			
18.75			-0.75	-18.75	=	15			
-0.75	y	=	15						
-0.75	y	=	-3.75	mph					
	y	=	5						
swimming	25	mph							
current     	5	mph