Step 1: Define variables.
Let the present age of Ramu be \( R \) and the present age of Somu be \( S \).
Step 2: Translate the conditions into equations.
Step 3: Simplify the equations.
From the first equation:
\[ R - 5 = 3S - 15 \implies R = 3S - 10. \]
From the second equation:
\[ R + 10 = 2S + 20 \implies R = 2S + 10. \]
Step 4: Solve the system of equations.
Set the two expressions for \( R \) equal to each other:
\[ 3S - 10 = 2S + 10. \]
Simplify:
\[ S = 20. \]
Substitute \( S = 20 \) into \( R = 3S - 10 \):
\[ R = 3(20) - 10 = 60 - 10 = 50. \]
Final Answer: The present ages of Ramu and Somu are \( \mathbf{50 \text{ and } 20} \), which corresponds to option \( \mathbf{(4)} \).