Step 1: Write the goodwill equation with an unknown rate.
Let the normal rate be $r$ percent. Normal profit is $5{,}00{,}000 \times r/100$. Super profit is $60{,}000$ minus that value.
Step 2: Put the numbers in the goodwill formula.
Goodwill is 3 times super profit, so
\[ 3\left(60{,}000 - 5{,}000\,r\right) = 30{,}000 \]
Step 3: Solve for r.
Divide both sides by 3.
\[ 60{,}000 - 5{,}000\,r = 10{,}000 \]
\[ 5{,}000\,r = 50{,}000 \]
\[ r = 10 \]
Step 4: Test the answer.
With $r = 10$, normal profit is Rs 50,000. Super profit is $60{,}000 - 50{,}000 = 10{,}000$. Goodwill is $3 \times 10{,}000 = 30{,}000$. This matches the question.
Step 5: Conclude.
The other rates fail. At 5% goodwill is Rs 1,05,000. At 15% and 20% the normal profit is at least Rs 75,000, so there is no super profit.
\[ \boxed{10\%} \]
Final Answer:
The normal rate of return is 10%.