Three odd numbers that add up to 30

What's the difference between: x≥0 and nonnegative integer. ?

In the diagram below? p is circumscribed about quadrilateral abcd. what is the value of x

At a kentucky friend chicken, a survey showed 2/3 of all people preferred skinless chicken over the regular chicken. if 2,400 people responded to the survey, how many people preferred regular chicken?