Answer:
$19,000 was invested at 5% and $16,000 was invested at 15%
Explanation:
Let
x ----> the amount invested at 5%
(35,000-x) ------> the amount invested at 15%
we know that
The total interest is equal to the interest of the amount invested at 5% plus the interest of the amount invested at 15%
![5\%=5/100=0.05](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jhl20c8f5ubhjsyyz592fpuf5qb3mcxvt0.png)
![15\%=15/100=0.15](https://img.qammunity.org/2020/formulas/mathematics/high-school/ww4aafo04izk0jcxxn8hvua3m2a4rpddxo.png)
so
![3,350=0.05x+0.15(35,000-x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5l0wtgue9qh2ku275ytzymlkstcgyc3one.png)
Solve for x
![3,350=0.05x+5,250-0.15x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/cb46yg1eqgcs5zop7zkujh9qz96zhi2yr6.png)
![0.15x-0.05x=5,250-3,350](https://img.qammunity.org/2020/formulas/mathematics/middle-school/55s79d8ceunhia7ldulmhv63w0wf7zxzoc.png)
![0.10x=1,900](https://img.qammunity.org/2020/formulas/mathematics/middle-school/4t6wsvhy4gganghbb8g3zw3lcwegozlss1.png)
![x=\$19,000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/syadzjkltktu62ct1ygx5yecgm222iruca.png)
![(35,000-x)=\$16,000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/c02kpfba6pvrfhxwcdara1mzgmch2pqfd5.png)
therefore
$19,000 was invested at 5% and $16,000 was invested at 15%