Question

One hundred riders from several countries participated in a bicycle race. Only eighty riders, including Juan and Charlie, finished the race. Juan finished 5th and Charlie was the winner. All the riders' countries of origin and finishing times were recorded on the race register. No two riders who finished had the same time and those who did not finish were recorded as DNF.

Based on this information, determine if each set is well-defined. Yes or No

The set of riders who finished minutes or more after the winner (Yes or No)
The set of the three least tired riders at the end (Yes or No)
The set of riders with the best-looking bicycles (Yes or No)
The set of riders who finished the race (Yes or No)
The set of countries of origin of the riders that didn't finish (Yes or No)

Answer 1

Finished minutes or more: Yes

Three least tired: No

Best looking bikes: No

Finished the race: Yes

Countries of origin of riders who didn't finish: Yes

Explanation:

Things displayed on the board: name of rider, country of origin, finishing time

Finished minutes or more: anyone who finished who wasn't in first

Three least tired: subjective information, not on the board

Best looking bikes: subjective information, not on the board

Finished the race: everyone who doesn't have DNF next to their name

Countries of origin of riders who didn't finish: countries of anyone with DNF next to their name