Question 501670
	--------price	----------------	quantity									
Coffee I	90	----------------			30	lb						
Coffee II	50	----------------			x	lb						
Mixture	60	----------------	30	+	x	lb						
												
90*30+50x=60	(	30	+	x	)
2700	+	50	x	=	1800	+	60	x				
50	x	+	-60	x	=	1800	-	-2700				
-10	x	=	-900									
/	-10											
x	=	90										
		90	lb		of	50	%	Coffee II