Question 318443
$600 at 9% per year, 
Interest for 1 year = 0.09*600= $54
and $800 at 12% per year.
Interest for 1 year = 0.12*800= $ 96
Total for 1 year = $150
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$150 1 year 
For $525 --- 525/150 = 3.5 years
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975 /150 = 6.5 years
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Time frame  is 3.5 years to 6.5 years