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 trails in a population
studies with the nth person selected

The skating rink rented 872 pairs of skates during april and may.why? : if the skating rink rented three times the pair of skates in april during may, they rented 654 skates. 218 x 3 = 654then, if they want to know how many they rented during both april and may, then you just add 654 (may) and 218 (april) to give you 872 pairs of skates for both months.654 + 218 = 872hope this !