Answer: Brian invested $16000 in Fund B .
Explanation:
Let x be the amount Brian invested in Fund B.
Given, The $8000 that he invested in Fund A returned a 4% profit. The amount that he invested in Fund B returned a 1% profit.
i.e. profit on Fund A = 4% of 8000 = 0.04 ×8000 = $320
Profit on Fund B = 1% of x = 0.01x
Together they earn 1% profit, i.e. Combined profit = 2% of (8000+x)
= 0.02(8000+x)
As per question,
Combined profit=Profit on Fund A+Profit on Fund B
![\Rightarrow\ 0.02(8000+x) =320+0.01x\\\\\Rightarrow\ 0.02(8000) +0.02x=320+0.01x\\\\\Rightarrow\ 160+0.02x=320+0.01x\\\\\Rightarrow\ 0.02x-0.01x=320-160\\\\\Rightarrow\ 0.01x=160\\\\\Rightarrow\ x=(160)/(0.01)\\\\\Rightarrow\ x=16000](https://img.qammunity.org/2021/formulas/mathematics/high-school/ge079i82v3c76zqc665fw12abx6aeyh2y3.png)
Hence, Brian invested $16000 in Fund B .