JNU SSS 2011 Question 96: Budget constraint and consumer equilibrium

In situation I : Price of good $X$ is twice the price of good $Y$; and the consumer spends his entire income on buying 6 units of good $X$ and 20 units of good $Y$. In situation II : Consumer's income is double of his income in situation I, price of good $Y$ is twice the price of good $Y$ in situation I, and the price of good $X$ is the same as in situation I. The consumer wants to continue consuming 20 units of good $Y$ in situation II. The maximum number of units of good $X$ that he can purchase in situation II is