Given:
The investment amount = $ 22954 part at 7% and rest at 5 %.
The interest earned from the amount invested at 7 % exceeds the interest earned from the amount invested at 5 % by $642.46
To find:
We need to find the investment amount at each rate.
Step-by-step explanation:
Let x be the investment amount at an interest rate of 7%
Let y be the investment amount at an interest rate of 5%
![x+y=22954](https://img.qammunity.org/2023/formulas/mathematics/college/nqg94zl02wyonka66oh7lvme9y61wxb3s8.png)
![x=22954-y](https://img.qammunity.org/2023/formulas/mathematics/college/dlyjhjohw0ka4w4s7uolz7qjjxabecyoua.png)
The interest earned from $22954-y at 7 % is
![=7\text{ \% of (22954}-y)](https://img.qammunity.org/2023/formulas/mathematics/college/hnc84rmme554mnvkb7s9q8c9uxv5jmkp66.png)
![=(7)/(100)*(22954-y)](https://img.qammunity.org/2023/formulas/mathematics/college/unru305r0w0eldylyxjgls08hejbdzsgnr.png)
![=1606.78-0.07y](https://img.qammunity.org/2023/formulas/mathematics/college/e6svp1qi7zizh007r6wnari2wx0xun8uzg.png)
The interest earned from $22954-y at 7 % is $1606.78-0.07y.
The interest earned from y at 5 % is
![=5\text{ \% of y}](https://img.qammunity.org/2023/formulas/mathematics/college/zf6o82d9ysdaf8aij4o8hw6cd2bbvorvk2.png)
![=(5)/(100)y](https://img.qammunity.org/2023/formulas/mathematics/college/gqpllpcxj0ys8zfl80esqezjlmyh8sz2o6.png)
![=0.05y](https://img.qammunity.org/2023/formulas/mathematics/college/o6bwa7hge6xg6unrofrogdpblx6zcxt3yp.png)
The interest earned from y at 5 % is 0.05y.
We can write the following equation from the given statement.
![1606.78-0.07y=0.05y+642.46](https://img.qammunity.org/2023/formulas/mathematics/college/v2h47n2w53wrsj2k6me46qu8kjgiymq9b9.png)
![1606.78-642.46=0.05y+0.07y](https://img.qammunity.org/2023/formulas/mathematics/college/tx5878oaidhlnukhg5vtntuuqn73lkefcj.png)
![964.32=0.12y](https://img.qammunity.org/2023/formulas/mathematics/college/b4wls1h1ix3uichfg2vvhn8jjqkkqd6lbt.png)
Dividing both sides by 0.12, we get
![(964.32)/(0.12)=(0.12y)/(0.12)](https://img.qammunity.org/2023/formulas/mathematics/college/a3ybx6sn8856fqwg7tc1li7112omkg6i96.png)
![8036=y](https://img.qammunity.org/2023/formulas/mathematics/college/uqmh5zfeemgitr9nkb858dqqam14eujph1.png)
Substitute y=8036 in x=22954-y, we get
![x=22954-8036](https://img.qammunity.org/2023/formulas/mathematics/college/xxe7gw4dqw85ipga24rdvbgm3b55x64cyl.png)
![x=14918](https://img.qammunity.org/2023/formulas/mathematics/college/jld5prqpodfvozpfzoygvnfjx5y086csfm.png)
Final answer:
The amount invested at an interest rate of 7% is $14,918
The amount invested at an interest rate of 5% is $8036.