Explanation:

- A invests Rs. X for 20 months, while B invests (X + 10) for 16 months. We compare these investments to their profit ratio later, which is 5:6.

- A's effective capital-time becomes 20X (X for 20 months).

- B's capital-time becomes 16(X + 10) (because (X + 10) is for 16 months).

- Setting up the ratio: 20X : 16(X + 10) = 5:6

- Simplify: 5(16X + 160) = 6(20X)

- Solve the equation:

- 80X + 800 = 120X

- 800 = 40X

- X = 20

- Value of B's investment is (X + 10), i.e., 20 + 10 = 30.

Correct Answer: Option 2, Rs. 30