The total amount invested by Isabella which she has invested at 4%, when the annual income from these three investments is $2025, is $25000.
Percentage of a number is the part of the number expressed in the in every hundred. Percentage of a number is expressed with the symbol '%' known as percentage symbol.
Let suppose the Isabella invested x dollars at 3%. Now, Isabella has twice as much money invested at 4% as she has invested at 3%. Thus,
[tex]\rm Invested \;at \;4\%=2x[/tex]
She has $500 more invested at 5% than she has at 3%. Thus,
[tex]\rm Invested \;at \;5\%=x+500[/tex]
The annual income from these three investments is $2025. Thus, the sum of all the three investement amount should be equal to $2025.
[tex]\dfrac{3}{100}(x)+\dfrac{4}{100}(2x)+\dfrac{5}{100}(x+500)=2025\\0.03x+0.08x+0.05x+25=20250.16x=2025-25\\x=\dfrac{2000}{0.16}\\x=25000[/tex]
Thus, he total amount invested by Isabella which she has invested at 4%, when the annual income from these three investments is $2025, is $25000.
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