VTMO 2026 - Grade 2 - Semifinal - SET 3 - Self-study Question 6

An, Bình, Châu and Dũng have 90 marbles altogether. Dũng says: “An and Bình together have 3 times as many marbles as Châu. An, Bình and Châu together have 2 times as many as I do.” How many marbles does Châu have?