Question 500026
	percent	----------------	quantity									
Alcohol I	31	----------------			5	ml						
Alcohol II	7	----------------			x	ml						
Mixture	15	----------------	5	+	x	ml						
												
31*5+7x	=15(5+x	)
155+7x	=	75	+	15	x				
7x-15x	=	75	-	-155				
-8x=	-80									
/	-8											
x	=	10										
		10	ml		of	7	%	Alcohol II