Then the big oil drum is more than the small oil drum: 50 * 6 = 300 (kg)
Replace, change the small oil drum into a large oil drum.
Every time you change a big oil drum, it is much less than a small one: 6+2 = 8 (kg).
Much less: 300-60 = 240 (kg)
Change (small oil drum available): 240/8 = 30 (times) (pieces)
Oil drums: 50-30 = 20 (pieces)
I don't know if I can be satisfied.
Hehe, come on! If you don't understand, ask again and answer honestly!