Answer:
The amount invested in the account that paid 8% was $18,000
The amount invested in the account that paid 10% was $6,000
The amount invested in the account that paid 12% was $26,000
Explanation:
Let
3x -----> the amount invested in the account that paid 8%
x -----> the amount invested in the account that paid 10%
$50,000-4x ----> the amount invested in the account that paid 12%
in this problem we have
![8\%=8/100=0.08\\10\%=10/100=0.10\\12\%=12/100=0.12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/b2was4a222roq7t3ozonpj8bzhf67aksb6.png)
we know that
![3x(0.08)+x(0.10)+(50,000-4x)(0.12)=5,160](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z3xdekxseaii4cxjhgj7pq0792lj6u9eb9.png)
Solve for x
![0.24x+0.10x+6,000-0.48x=5,160](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zooq47v5lml400so3oetek700l5xet5f71.png)
![0.48x-0.24x-0.10x=6,000-5,160](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3447trztxqqv2ujjute1sy22dw5aigaza2.png)
![0.14x=840](https://img.qammunity.org/2020/formulas/mathematics/middle-school/v19iths6fvfiuv8uq4z1zjx2ned0vlfww5.png)
![x=\$6,000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/eakyxh9h4hn99waqyvbot27jgw6gawzbzk.png)
![3x=\$18,000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/sp9e6pxlbo8ve1aoj56wutck4o93hkwlb3.png)
![\$50,000-4x=\$26,000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lv1amyutzjwct70k85r6fnct6g87h86i2b.png)
therefore
The amount invested in the account that paid 8% was $18,000
The amount invested in the account that paid 10% was $6,000
The amount invested in the account that paid 12% was $26,000