Four girls P, Q, R and S are studying languages in a university. P is learning French and Dutch. Q is learning Chinese and Japanese. R is learning Spanish and French. Sis learning Dutch and Japanese. Given that: French is easier than Dutch; Chinese is harder than Japanese; Dutch is easier than Japanese, and Spanish is easier than French. Based on the above information, which girl is learning the most difficult pair of languages?

The correct option is Q.

To determine which girl is learning the most difficult pair of languages, we first need to establish the relative difficulty of all the languages mentioned: French, Dutch, Chinese, Japanese, and Spanish.

Let us analyze the given difficulty relationships:
1. French is easier than Dutch (French < Dutch).
2. Dutch is easier than Japanese (Dutch < Japanese).
3. Combining these two, we get: Spanish/French < Dutch < Japanese.
4. Spanish is easier than French (Spanish < French).
5. Chinese is harder than Japanese (Japanese < Chinese).

By ordering the languages from easiest to hardest based on these relationships, we get:
Spanish < French < Dutch < Japanese < Chinese.

Now, let us list the pair of languages each girl is learning and evaluate their difficulties:
• P is learning French and Dutch.
• Q is learning Chinese and Japanese.
• R is learning Spanish and French.
• S is learning Dutch and Japanese.

Comparing the pairs, Chinese and Japanese are the two most difficult languages in the entire group. Since girl Q is learning Chinese and Japanese, she is learning the most difficult pair of languages.