Question 1
Two people walk towards one another along a straight line at different constant speeds. At the same instant each releases a dog to run forwards. The dogs have the same constant speed. Each dog runs to the other person, then returns to its own owner. Which dog returns first: the faster walker’s dog or the slower walker’s dog? (3 points)
Neutral editorial illustration.
Practice scoring adds all whole-question scores (maximum 23). Official ITOT scoring adds only the three highest whole-question scores (maximum 16), after summing subparts within each question. The importer does not enforce best-three scoring. Duration: 300 minutes from historical organizer general rules, not an individually printed duration on this paper.
Neutral editorial illustration.
Practice scoring adds all whole-question scores (maximum 23). Official ITOT scoring adds only the three highest whole-question scores (maximum 16), after summing subparts within each question. The importer does not enforce best-three scoring. Duration: 300 minutes from historical organizer general rules, not an individually printed duration on this paper.