Question 1202398


Let boat	speed	=x	mph	in still water				
Let current 	speed	=y	mph					
against current  x-y		time taken 140.00	hours					
with wind  x+y		time taken 14.00	hours					
								
Distance = same=		140	miles					
t=d/r		

Upstream time equation		
				
140	/	(	x	-	y	)=	140.00	

Downstream  time equation

140.00	/(	x	+	1	y)	=	14.00	

	x		1y	=	1.00	....................1	

140	/	(	x-		y	)=	14.00	
140	/(	x	-	1	y)	=	14.00	

	x	-	y	=	10.00	...............2	

Multiply (1) by	1.00							
Multiply (2) by	1.00							
we get								
	x	+	y	=	1		
x	-	y	=	10		
2	x	=	11	
				
/	2
							
x	=	5.5	mph					
								
plug value of x in (1)	
							
x		-	y	=	1		
5.5			-	y	=	1.00		
-y	=	1.00	-5.5				
-1	y	=	-4.50					
	y	=	4.5	mph		

Complete by writing the answer