Sayed started a software business by investing Tk. 20,000. After 6 months, Rafi joined him with a capital of Tk. 30,000. After 3 years, they earned a profit of Tk. 13,950. What was Sayed's share in the profit?

Question: Sayed started a software business by investing Tk. 20,000. After 6 months, Rafi joined him with a capital of Tk. 30,000. After 3 years, they earned a profit of Tk. 13,950. What was Sayed's share in the profit?
A) Tk. 6200
B) Tk. 6400
C) Tk. 7750
D) Tk. 9300

Solution:
Total time = 3 years
= 3 × 12 months
= 36 months.

Sayed's capital-time = 20,000 × 36 = 720,000.

Rafi joined after 6 months.
Rafi's time = 30 months.
∴ Rafi's capital-time = 30,000 × 30 = 900,000.

∴ Profit ratio = 720,000 : 900,000 = 72 : 90 = 4 : 5.
Total profit = 13,950.
Total ratio parts = 9.

∴ Sayed's share = (4/9) × 13,950
= 4 × 1550
= Tk. 6200.