Question 1008327

skater		x	km/h					
cyclist		20	faster	x	+	20	km/h	
								
skater		30	km  					
cyclist		80	km  					
skater	time	=	cyclist		time			
t=d/r								
30	/	x	=	80	/(	x	+	20
cross multiply								
30	(	x	+	20	)	=	80	x
30	x	+	600	=	80	x		
30	x	-	80	x	=	-600		
-50	x	=	-600					
/	-50							
x	=	12      	km/h
					
								
12    	km/h	skater