Question 415093
A bank loaned out $7,500 part at 12% annual interest and the rest at 8% annual interest. The total interest earned for both loans was $680.00. How much was loaned at each rate?

12.00%		per annum	-------------	x
8.00%		per annum	------------	y
total investment	75000			
Interest-----	$680.00	

...
		
x+y=7500	------------------------1				
12.00%	x+8.00%	y=$680.00			
Multiply by 100							
12x+8y=	$68,000.00		--------2	
									
Multiply (1) by			-12						
we get									
									
-12x-12	y=-90000			
									
Add this to (2)									
									
-4y=-$22,000.00			
									
divide by-4							
									
y=$5,500.00investment at 	8.00%
Balance	$2,000.00 investment at 	12.00%