Let the total profit be Rs 33,000, and the total time be 2 years.
The investments of A, B, and C are:
A's investment = Rs 20,000
B's investment = Rs 15,000
C's investment = Rs 20,000
Since C joined the business after 6 months, the time for each partner's investment is as follows:
A's time = 2 years = 24 months
B's time = 24 months
C's time = 18 months (as C joined after 6 months)
Now, we calculate the effective capital invested by each partner using the formula:
\[
\text{Effective Capital} = \text{Investment} \times \text{Time}
\]
For A:
\[
\text{Effective Capital of A} = 20,000 \times 24 = 480,000
\]
For B:
\[
\text{Effective Capital of B} = 15,000 \times 24 = 360,000
\]
For C:
\[
\text{Effective Capital of C} = 20,000 \times 18 = 360,000
\]
The total effective capital is:
\[
\text{Total Effective Capital} = 480,000 + 360,000 + 360,000 = 1,200,000
\]
Now, the share of B in the profit is calculated by the ratio of B's effective capital to the total effective capital:
\[
\text{Share of B} = \frac{\text{Effective Capital of B}}{\text{Total Effective Capital}} \times \text{Total Profit}
\]
\[
\text{Share of B} = \frac{360,000}{1,200,000} \times 33,000 = 9,900
\]
Thus, the share of B in the profit is Rs 9,900.