Answer:
The return after taxes is 7.9%
Explanation:
At the start of the year the portfolio is valued at $365,000.
At the end, his portfolio has returns by dividends ($3,579), interests ($2,783) and portolio's valuation (389,648-365,000=$24,648).
The tax is applied to the dividends and interests, as:
Tax = 0.35 * (3579+2783) = 0.35*6362 = $2,226.70
We can then calculate the investor's return as
R = profit after taxes / initial portfolio valuation
R = ((3579 + 2783 - 2226.70)+24648)/365000
R= 28,783.30 / 365,000 = 0.079 = 7.9%