<PRE><B>Question 551028</B>
boat  	speed	=	60	kmph											
current speed =	x	kmph						
upstream speed 	=60-x 		
downstream speed =60+x 													
Total distance =100km		Total Time=	12.00	hours  								
Time upstream + time downstream = 
100/(60-x)+100/(60+x)=	12
100(60+x)+100(60-x)=	12
6000+100x+6000-100x=12(15^2-x^2)
12000=12(3600-x^2)					
12000	=	43200	-12	X^2								
12	X ^2	=	31200										
X^2=2600											
x=	50.99	km/h										
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