Given that $r$ and $s$ are relatively prime positive integers such that $\dfrac{r}{s}=\dfrac{2(\sqrt{2}+\sqrt{10})}{5\left(\sqrt{3+\sqrt{5}}\right)}$, find $r$ and $s$.
1. **Given Expression:**
   \[
   \frac{r}{s} = \frac{2(\sqrt{2} + \sqrt{10})}{5\sqrt{3 + \sqrt{5}}}
   \]

2. **Square Both Sides:**
   \[
   \left(\frac{r}{s}\right)^2 = \left(\frac{2(\sqrt{2} + \sqrt{10})}{5\sqrt{3 + \sqrt{5}}}\right)^2
   \]

3. **Simplify the Right-Hand Side:**
   \[
   \left(\frac{2(\sqrt{2} + \sqrt{10})}{5\sqrt{3 + \sqrt{5}}}\right)^2 = \frac{4(\sqrt{2} + \sqrt{10})^2}{25(3 + \sqrt{5})}
   \]

4. **Expand the Numerator:**
   \[
   (\sqrt{2} + \sqrt{10})^2 = 2 + 2\sqrt{20} + 10 = 12 + 4\sqrt{5}
   \]
   So,
   \[
   4(\sqrt{2} + \sqrt{10})^2 = 4(12 + 4\sqrt{5}) = 48 + 16\sqrt{5}
   \]

5. **Simplify the Denominator:**
   \[
   25(3 + \sqrt{5})
   \]

6. **Combine the Results:**
   \[
   \left(\frac{r}{s}\right)^2 = \frac{48 + 16\sqrt{5}}{75 + 25\sqrt{5}}
   \]

7. **Rationalize the Denominator:**
   Multiply the numerator and the denominator by the conjugate of the denominator:
   \[
   \frac{(48 + 16\sqrt{5})(75 - 25\sqrt{5})}{(75 + 25\sqrt{5})(75 - 25\sqrt{5})}
   \]

8. **Simplify the Denominator:**
   \[
   (75 + 25\sqrt{5})(75 - 25\sqrt{5}) = 75^2 - (25\sqrt{5})^2 = 5625 - 3125 = 2500
   \]

9. **Simplify the Numerator:**
   \[
   (48 + 16\sqrt{5})(75 - 25\sqrt{5}) = 48 \cdot 75 - 48 \cdot 25\sqrt{5} + 16\sqrt{5} \cdot 75 - 16\sqrt{5} \cdot 25\sqrt{5}
   \]
   \[
   = 3600 - 1200\sqrt{5} + 1200\sqrt{5} - 2000 = 3600 - 2000 = 1600
   \]

10. **Combine the Results:**
    \[
    \left(\frac{r}{s}\right)^2 = \frac{1600}{2500} = \frac{16}{25}
    \]

11. **Take the Square Root:**
    \[
    \frac{r}{s} = \pm \frac{4}{5}
    \]

12. **Since \(r\) and \(s\) are relatively prime positive integers:**
    \[
    \frac{r}{s} = \frac{4}{5}
    \]

The final answer is \( \boxed{ (r, s) = (4, 5) } \)