<PRE><B>Question 667740</B>
Investment I		7.00%	2000													
Investment II		4.00%	5000													
Investment III		6.00%	x													
																
Total  		5.00%														
The sum of  individual interest earned 	=	5.00%	of	Total investment									
Total Interest																
7.00%*2000+4.00%*5000+6.00%x=5.00%(2000+5000+x)
140+	200	+	6.00%	x	=	350	+	5.00%	x						
6.00%	x-	5.00%	x=	350	-140	-200										
1.00%	x=	10														
	x=	1000														
He has to invest $		1000														
																
CHECK																
																
140	200	60		=	400											
																
Total = 	8000															
5.00%	on	8000	=	400												
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