A began a business with Rs. 18000 and was joined afterward by B with Rs. 24000. When did B join if the profits at the end of the year were divided in the ratio 9: 7?

A after 4 months

B after 5 months

C after 6 months

D after 7 months

E after 8 months

Correct Answer: Option B

Let’s assume that B participated in the business for x months.

We know that, ratio of shares of profits of A and B = Ratio of their investments

\(\Rightarrow \;\frac{9}{7}\; = \;\frac{{18000\; \times 12}}{{24000\; \times \;x}}\)

⇒ x = 7

⇒ B was a part of the business for 7 months.

⇒ B joined the business after: (12 – 7) = 5 months from the day A started business.