In this exercise, we should focus on the answers in order to make the appropriate questions. The questions are made out of the information given in the answers. Let's find it and understand what was the question.
1. CHELA El libro de periodismo está encima de la mesa.
The crucial information here is the location of the book. To ask for the location of something, we use WHERE (dónde).
MIREYA ¿Dónde está el libro de periodismo?
2. MIREYA Sí, me gusta mucho estudiar periodismo.
As we have yes (sí), we understand that is a yes/no question. The rest of the sentence tells us what Chela asked. When we want to make a yes/no question in Spanish, we just pust question marks and change the intonation (speech).
CHELA ¿Te gusta estudiar periodismo?
3. MIREYA Porque la clase es muy interesante.
When the response is porque (because), the question is normally why?
CHELA ¿Por qué?
4. CHELA Este semestre tomo matemáticas, química y física.
The information given here are the subjects she takes.
MIREYA ¿Qué asignaturas tomas este semestre?
5. CHELA En la clase de matemáticas hay sesenta chicos.
The main part of the response is the number of guys in the class.
MIREYA ¿Cuántos chicos hay en la clase de matemáticas?