Question 9
Paul has three tubes of balls as shown.
Pressing A, B or C opens that gate for exactly one ball, which falls into storage (“Kho dự trữ”). The balls in storage must be in increasing order from bottom to top. What is the greatest number of balls that can enter storage?
Pressing A, B or C opens that gate for exactly one ball, which falls into storage (“Kho dự trữ”). The balls in storage must be in increasing order from bottom to top. What is the greatest number of balls that can enter storage?