In an exam 66 % of the candidates passed. How many passed if there were 3000 candidates?

Which of the following parabolas opens down?

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values

What’s the answer? and how do i solve it ?