Answer
To know how much Bob invested in the account that paid 5%, we shall use the relation below
[tex]\frac{5}{100}x+\frac{6}{100}(10000-x)=540[/tex]Where x is the amount invested in an account that paid 5% simple interest and (10000 - x) represents, the amount invested in an account that paid 6% simple interest.
[tex]\begin{gathered} \Rightarrow0.05x+0.06(10000-x)=540 \\ 0.05x+600-0.06x=540 \\ 0.05x-0.06x=540-600 \\ -0.01x=-60 \\ x=\frac{60}{0.01} \\ x=6000 \end{gathered}[/tex]Therefore, $6,000 is the amount invested in the account that paid 5% simple interest
Now, the amount invested in an account that paid 6% simple interest would be
[tex]\begin{gathered} =10000-6000 \\ =4000 \end{gathered}[/tex]∴ $4,000 is invested in an account that paid 6% simple interest.