Answer:
1. ¿Va a viajar a Perú tu primo Andrés?
2. ¿Vas a buscar una tienda de computadoras en el centro comercial?
3. ¿Vamos a encontrar muchas rebajas en el centro?
4. ¿Va María a pagar las sandalias en la caja?
Explanation:
In this exercise you have to answer the questions negatively indicating that what is asked has already happened.
The correct structure in Spanish for this type of sentences is:
No, + ya + subject (in some cases) + past form of the verb + object.