Two machines, A and B, are used to fill small cube-shaped boxes with a side length of 10 cm. Machine A can fill the box in 5 minutes, while Machine B can fill the same box in 3 minutes. If both machines start filling boxes at the same time, how long will it take, in minutes, for them to fill a total of 10 boxes working together? Let's think step by step and output the final answer within \boxed{}.
user