Bank Interest question

lisamg9657

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Jun 28, 2013
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Okay here's my question about how to figure out how much is invested to get the answer for each percentages. Susan invests [FONT=MathJax_Main]3[/FONT] times as much money at [FONT=MathJax_Main]13[FONT=MathJax_Main]%[/FONT][/FONT] as she does at [FONT=MathJax_Main]9[FONT=MathJax_Main]%[/FONT][/FONT]. If her total interest after [FONT=MathJax_Main]1[/FONT] year is [FONT=MathJax_Main]$[FONT=MathJax_Main]1920[/FONT][/FONT], how much does she have invested at each rate? Now I need to figure out how much was put into each account. How do I get the total amount to figure this out for each one? Totally lost!:confused:
 
Okay here's my question about how to figure out how much is invested to get the answer for each percentages. Susan invests [FONT=MathJax_Main]3[/FONT] times as much money at [FONT=MathJax_Main]13[FONT=MathJax_Main]%[/FONT][/FONT] as she does at [FONT=MathJax_Main]9[FONT=MathJax_Main]%[/FONT][/FONT]. If her total interest after [FONT=MathJax_Main]1[/FONT] year is [FONT=MathJax_Main]$[FONT=MathJax_Main]1920[/FONT][/FONT], how much does she have invested at each rate? Now I need to figure out how much was put into each account. How do I get the total amount to figure this out for each one? Totally lost!:confused:
let x be the amount invested at 9%. Then 3x is the amount invested at 13%. The interest return by the money invested at 9% is .09x. The interest returned by the money invested at 13% is (.13)(3x)= .39x. The total interest is, of course, .09x+ .39x= 1920. Solve that equation for x.
 
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