Need help plz somebody

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected

What integer is equivalent to 9 3/2

Julia spends $5.25 on gas for her lawn mower. she earns $13.00 mowing her neighbor's yard. what is julia's profit?