X and Y enter into a partnership with capitals in the ratio 5 : 6 and at the end of 8 months, X withdraws. If they receive profit in the ratio of 5 : 9. Find how long Y's capital was used.

Correct Answer: 12 months
Let the capitals of Y was used for T months
According to the question,
$$\eqalign{ & \frac{{5 \times 8}}{{6 \times {\text{T}}}}{\text{ = }}\frac{5}{9} \cr & \Rightarrow {\text{T}} = {\text{12 months}} \cr} $$
Hence capital of Y was used for = 12 months