P starts a business with Tk 6000 and after 3 months, Q joins with P as his partner. After a year, the profit is divided in the ratio 4 : 5. What is Q's contribution in the capital?

Question: P starts a business with Tk 6000 and after 3 months, Q joins with P as his partner. After a year, the profit is divided in the ratio 4 : 5. What is Q's contribution in the capital?

Solution:
Let Q's capital be Tk x
∴ P's share in 12 months = 6000 × 12
And, Q's share in 9 months = 9x
Then,
(6000 × 12)/(9x) = 4/5
⇒ 72000/9x = 4/5
⇒ 72000 = 36x/5
⇒ 72000 × 5 = 36x
⇒ 360000 = 36x
⇒ x = 10000