Concept:
In partnership problems, profit is divided in the ratio of capital × time.
Thus, each partner’s share depends on the amount of money invested and the duration for which it was invested.
\[
\text{Profit ratio} \propto (\text{Capital} \times \text{Time})
\]
Step 1: Calculate capital–time product for each partner.
\[
A: 50,000 \times 12 = 600,000
\]
\[
B: 40,000 \times 12 = 480,000
\]
C joins after 6 months:
\[
C: 80,000 \times 6 = 480,000
\]
Step 2: Find the ratio of their investments.
\[
A:B:C = 600,000 : 480,000 : 480,000
\]
Dividing by \(120,000\):
\[
A:B:C = 5:4:4
\]
Step 3: Divide the total profit according to the ratio.
Total ratio parts:
\[
5+4+4=13
\]
Total profit = ₹25,000
\[
\text{Value of one part}=\frac{25000}{13}
\]
Step 4: Calculate individual shares.
\[
A=\frac{5}{13}\times 25000=\frac{125000}{13}\approx ₹9615.38
\]
\[
B=\frac{4}{13}\times 25000=\frac{100000}{13}\approx ₹7692.31
\]
\[
C=\frac{4}{13}\times 25000=\frac{100000}{13}\approx ₹7692.31
\]
Step 5: Final distribution of profit.
\[
A = ₹9615.38,\quad
B = ₹7692.31,\quad
C = ₹7692.31
\]