Question 912195
"$2500 is invested at 2% interest" so you earn 2500*0.02 = 50 dollars in interest alone in one year.


Let x = amount of money invested at 7%


You will earn 0.07x dollars in interest alone 


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Total Interest Earned: 50 + 0.07x


Total Amount Invested: 2500 + x


The ratio of amount earned to amount invested is forced to be 6%



(Total Interest Earned)/(Total Amount Invested) = target rate of return


(50 + 0.07x)/(2500 + x) = 0.06


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Now solve for x

<pre>
	(50 + 0.07x)/(2500 + x) = 0.06
	
	50 + 0.07x = 0.06(2500 + x)
	
	50 + 0.07x = 0.06(2500) + 0.06(x)
	
	50 + 0.07x = 150 + 0.06x
	
	0.07x - 0.06x = 150 - 50
	
	0.01x = 100
	
	x = 100/0.01
	
	x = 10,000
</pre>

So you need to invest <font color="red">$10,000</font> at 7% so that the total return of both investments average 6%