MYTS 2018 — Grade 5 — Round 1 Question 10

Points $A,B,C,D$ divide a circular track into equal arcs as shown. Hải starts at $A$ and Phượng at $B$, simultaneously and clockwise. Hải’s speed is $6/5$ of Phượng’s. How many laps has Hải run when first catching Phượng?