Answer:
$9,000 (amount invested at 3.8%)
$11,000 (amount invested at 8.1%)
Explanation:
Let us calculate the total interest earned by both investments
Interest earned= 0.06165* 20,000= $ 1,233
Let principal invested at 3.8% be X
Use formula Interest= principal* rate*time in years
Interest= X*0.038*1= 0.038X
Principal invested at 8.1% be (20,000-X)
So Interest = (20,000-X)*0.081*1= 1,620-0.081X
Total interest earned = Interest at 3.8% + Interest at 8.1%
1,233= 0.038X + 1,620 -0.081X
Rearranging
0.043X= 387
X= 387/0.043
X= $9,000 (amount invested at 3.8%)
Substitute in equation
Principal invested at 8.1%= 20,000-X
= 20,000- 9,000
= $11,000 (amount invested at 8.1%)
