Question 560968
first part	41	miles												
second part	8	miles												
														
speed in first part	xmph										
speed second part	x-5	mph										
Total rowing time3	hours											
Time first part	41/x								
Time second part8/(x-5)							
														
Time first part + time second part =	3	hours										
														
41/x	+	8/(x-5)	=3		
LCD =	x*(x-5	)						
multiply the equation by the LCD														
we get														
41*(x-5	)+8x=3(x(x-5))
41x-205	+8x=3X^2-15
64x-205	=3X^2									
3X^2-64x+205=	0						
3	X^2+	-64	x+	205	=				
Find the roots of the equation by quadratic formula			
a=	3	b=	-64	c=	205					b^2-4ac=	4096	-	-2460											
b^2-4ac=	1636	
{{{sqrt(	1636	)}}}=	40.45							
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}														
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}														
x1=(	64	+	40.45	)/	6									
x1=	17.41												
x2=(	64	-40.45	) /	6										
x2= 	3.93												
Ignore negative value														
x	=	17.41	mph	

first part speed = 17.41 mph
second part speed = 12.41 mph						
														
m.ananth@hotmail.ca