Question 1181173
Type	R	----------------			quantity									
Brazilian coffee	30	----------------			x	kg								
Columbian coffee	51	----------------	50	-	x	kg								
Mixture	42.60	----------------	50											
														
30	x	+	51	(	50	-	x	)	=	50.00	*	42.60		
														
30	x	+	2550	-	51	x	=			2130.00				
30	x	-	51	x			=	2130	-	2550				
-21	x			=	-420									
/	-21													
	x			=	20		kg					Brazilian coffee		
					30		kg					Columbian coffee