This is the 559th most frequent Spanish word.
suficiente
Enough; sufficient.
In this sentence, 'suficiente' is used as an adjective to describe a sufficient quantity of 'dinero' (money).
Tengo suficiente dinero para comprar el libro.
I have enough money to buy the book.
'Suficiente' acts as an adjective here, qualifying 'comida' (food) to denote adequacy in quantity.
¿Hay suficiente comida para todos los invitados?
Is there enough food for all the guests?
Here, 'suficiente' functions as an adverb modifying the verb 'estudié', indicating to what extent the action was performed.