Answer:
1. Baldini
2. aplicada a los estudios
3. hijastro
4. dos
5. Carlos Jose, dieciseis, la quimica.
6. Abuelo (I think, but I'm not sure)
Explanation:
I answered by following the reading you left below, I hope it helps.
The answer is Un Vendedor
Un precio means a price
Una moneda means a coin
Un Vendedor means a Vendor/Salesman
Una Compra means a purchase