A solution of A and B with 30 moles present of A is in equilibrium with its vapour which contain 60 mole percent of A. Assuming that the solution and the vapour behave ideally, calculate the ratio of the vapour pressures of pure A and pure B.

Explanation

To solve the problem of calculating the ratio of the vapor pressures of pure A and pure B, we will follow these steps:

### Step 1: Understand the Given Data
We have a solution containing 30 moles of A. The vapor in equilibrium with this solution contains 60 mole percent of A. This means:
- Moles of A = 30 moles
- Mole fraction of A in the vapor (Y_A) = 0.6
- Mole fraction of B in the vapor (Y_B) = 1 - Y_A = 0.4

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